UNIVERSITY    OF    CALIFORNIA    PUBLICATIONS 

IN 

AGRICULTURAL    SCIENCE 

Vol.  3,  No.  12,  pp.  369-498,  33  text-figs.,  pis.  43-74  June  30,  1919 


ARE   SOILS  MAPPED  UNDER  A  GIVEN  TYPE 

NAME  BY  THE  BUREAU  OF  SOILS  METHOD 

CLOSELY  SIMILAR  TO  ONE  ANOTHER? 


BY 

ROBERT  LAKIMORE  PENDLETON 


CONTENTS 

PAGE 

Foreword    369 

Introduction 370 

Need  of  a  classification  of  soils  371 

Historical  development  of  the  classification  of  soils  371 

Plan  of  the  present  study  376 

Discussion  of  results   '. 377 

Mechanical   analysis   380 

Chemical  data  395 

Bacteriological  data  414 

Greenhouse  data  432 

General  discussion  467 

Summary    481 

Appendices  483 

A.  Methods  and  technique  483 

B.  Soil  sample  locations  490 

FOREWORD 

It  is  due  the  author,  as  well  as  to  the  undersigned,  that  a  few 
words  be  said  by  way  of  preparing  the  reader  for  what  follows  in  this 
paper.  It  will  be  observed,  first,  that  the  manuscript  was,  for  an 
unusually  long  time,  in  the  printer's  hands.  Those  who  appreciate, 
as  few  do  today,  the  great  rapidity  with  which  the  theories  and  the 
methods  in  soil  and  plant  study  change,  will  readily  catch  the  signifi- 
cance of  the  foregoing  sentence.  Much  of  the  work  done  by  Mr. 
Pendleton  and  some  of  the  methods  used  may  now  properly  be  con- 
sidered obsolete,  or,  conservatively  speaking,  at  least  obsolescent. 
Nevertheless,  I  deem  it  of  some  importance  to  give  the  results  obtained 
in  more  or  less  detail,  because  of  their  historical  value,  and  because  Mr. 


370  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

Pendleton's  residence  in  India  since  the  paper  was  written  by  him 
has  rendered  satisfactory  changes  and  deletions  practically  impossible. 
Under  these  circumstances,  with  the  burden  of  preparing  the  paper 
for  the  press  and  the  reading  of  the  proof  falling  to  me,  the  author 
cannot  well  be  held  responsible  for  the  inaccuracies  and  the  infelicities 
of  expression  which  have  been  carried  over  from  the  original  manu- 
script without  change.  Moreover,  the  investigation  was  carried  out 
under  my  direction,  and  the  plan  of  attack  on  the  problem,  together 
with  the  methods  employed,  were  suggested  by  me.  Much  that,  in  the 
light  of  present  knowledge,  is  superfluous  or  patently  inexact  or 
erroneous  in  the  paper  is  due  to  points  of  view  held  by  me  in  1915, 
but  now  happily  discarded.  For  all  these,  I  assume  the  entire 
responsibility,  and  absolve  Mr.  Pendleton  in  that  regard. 

On  the  other  hand,  the  work  having  been  carried  out  at  my  sugges- 
tion and  under  my  direction,  I  feel  constrained,  in  justice  to  myself, 
to  say  that  the  views  expressed  in  this  paper,  and  the  conclusions 
drawn  are  wholly  Mr.  Pendleton's  and  are  not  in  agreement  with  those 
held  by  me.  I  fail  to  see  the  cogency  of  the  arguments  set  forth  for 
soil  classification  and  mapping  at  this  juncture  in  soil  studies,  and 
cannot  admit  the  pertinence  of  the  analogy  between  classification  of 
other  objects  and  of  soils  which  the  author  of  this  paper  employs. 
My  own  general  conclusion  from  the  results  obtained  by  Mr.  Pendle- 
ton is  that  they  cast  grave  doubt  on  the  validity  of  the  Bureau  of  Soils 
method  of  soil  classification  and  mapping,  and,  incidentally  on  all 
methods  devised  for  that  purpose  to  date.  I  cannot  see  how  such 
methods  can  serve  us  in  scientific  work  at  all,  and,  from  the  practical 
standpoint,  it  would  surely  seem  that  guides  for  the  purchaser  of  land 
could  be  arranged  more  cheaply  and  less  elaborately  than  by  the  soil 
mapping  methods  extant.  This  statement  has  particular  reference  to 
the  subdivision  of  types  very  minutely,  such  as,  for  example,  sandy 
silty  clay,  clay  loam  adobe,  etc.  Such  minute  classification  and  sub- 
division in  view  of  the  present  state  of  our  knowledge  of  soils,  is 
analogous,  in  my  opinion,  to  carrying  figures  out  to  four  decimal 
places  when  it  is  known  that  the  accuracy  of  the  method  makes  it 
impossible  for  them  to  be  correct  beyond  the  first  decimal  place.  In 
support  of  this  seemingly  radical  conclusion,  the  reader  will  find  much 
of  interest  in  the  recent  studies  of  this  laboratory  on  variability  in 
soils,  which  have  already  appeared  in  this  same  series. 

Chas.  B.  Lipman. 


INTRODUCTION 

For  several  years  the  University  of  California  has  been  cooperating 
with  the  United  States  Bureau  of  Soils  in  the  mapping  of  the  soils  of 
the  agricultural  portions  of  the  State  of  California.  The  system  of 
mapping  used  is  that  developed  by  the  Bureau  of  Soils.  During  the 
year  1914-1915  the  writer,  representing  the  University  of  California, 
was  engaged  in  some  of  this  soil  survey  work.  In  that  year,  in  the 
field,  many  questions  arose  regarding  the  criteria  used,  the  methods. 


1919]  Pendleton:   A  Study  of  Soil  Types  371 

and  the  results  of  the  scheme  of  mapping.  It  was  thought  that  pos- 
sibly some  of  the  many  questions  could  be  answered  through  a  labora- 
tory study  of  some  typical  soils.  This  paper  is  a  description  of  cer- 
tain parts  of  the  Avork  done  in  this  connection. 


THE  NEED  OP  A  CLASSIFICATION  OF  SOILS 

Since  soils  consist  of  a  number  of  more  or  less  distinct  groups  they 
are  fitting  subjects  for  classification.  In  fact,  it  is  my  belief  that  it 
is  as  necessary  to  have  a  classification  for  soils  as  for  any  other  group 
of  natural  objects  in  order  that  "the  various  and  complex  relations 
may  be  shown  as  far  as  practicable,"1  and  that  there  be  a  definite 
basis  for  systematic  and  thorough  investigations.2  The  advantages  of 
a  classification  of  soils  are  apparent.  But  because  soils  grade  gradu- 
ally into  one  another,  rather  than  exist  as  discrete  individuals  which 
can  be  more  easily  considered  and  treated  from  a  systematic  stand- 
point, the  problem  of  evolving  a  satisfactory  classification  has  been 
particularly  difficult.  The  many  and  diverse  classifications  proposed, 
and  the  difficulty  of  applying  many  of  these  classifications  under  con- 
ditions other  than  those  for  which  they  were  evolved,  testify  to  the 
difficulty  of  the  task  in  question. 

The  mapping  of  soils  without  a  classification  is  impossible,  and 
so  a  brief  summary  of  the  development  of  soil  mapping  will  bear  a 
close  relation  to  the  development  of  soil  classification. 


HISTORICAL    DEVELOPMENT    OF    THE    CLASSIFICATION 

OF  SOILS 

The  early  history  of  the  making  of  soil  maps  is  that  of  geologic 
maps  as  well,  when  soils,  from  the  agricultural  standpoint,  and  the 
less  distinct  geological  formations  as  such,  were  not  sharply  distin- 
guished. Blanck3  has  an  excellent  treatment  of  the  development  of 
soil  mapping  and  of  the  modern  continental  European  conceptions  of 
the  nature  and  significance  of  soil  maps.  According  to  Blanck  the 
earliest  record  of  a  proposal  to  make  a  map  to  show  something  of  the 
nature  of  the  actual  material  composing  the  surface  of  the  earth  is 
that  of  Lister's  proposal,  in  1683,  to  the  Royal  Society  of  London. 


i  Coffey,  G.  N.,  Proc.  Amer.  Soc.  Agron.,  vol.  1  (1909),  p.  175. 
2  Cameron,  F.  K.,  Eighth  Internat.  Cong.  Chem.,  vol.  26  (1912),  sees,  via-xib; 
app.  pp.  699-706. 

sFuhling,  Landw.  Ztg.,  vol.  60  (1911),  pp.  121-45. 


372  University  of  Calif ornia  Publications  in  Agricultural  Sciences        [Vol.  3 

But  it  was  not  until  1743  that  Packe  executed  a  map  of  Kent,  showing 
the  occurrence  of  minerals  by  symbols.  Apparently  the  next  advance 
was  by  the  Germans,  when  Fuchsel,  1773,  and  Gloser,  1775,  first  used 
colors  to  show  granite,  limestone,  etc.  This  work  constituted  the  first 
real  geologic  map  in  the  modern  sense.  There  was  not  much  activity 
in  this  line  of  geologic  work  until  1870  or  later.  Such  activity  as  there 
was  showed  a  lack  of  emphasis  on  soils  in  the  agricultural  sense  of 
the  term. 

The  work  on  the  geologic  drifts  of  northern  Europe,  and  studies  of 
the  more  recent  lowland  formations  and  soils  of  Germany  led  to  soil 
mapping.  The  first  real  soil  map,  according  to  Blanck,  was  prepared 
by  Benningsten-Forder  of  Halle,  in  1864-67 ;  while  Carnot4  states 
that  in  1863  M.  Scipion  Gras  used  superposable  maps  of  the  Depart- 
ment of  Isere,  showing  (1)  geology,  (2)  agricultural  soils,  (3)  alti- 
tudes of  agricultural  regions,  and  (4)  culture.  The  first  true  geologic- 
agronomic  map  published  by  the  Preussischegeologische  Landesan- 
stalt  appeared  in  1878. 

The  school  of  soil  classification  and  mapping  just  mentioned,  using 
the  geologic  maps  and  methods  as  a  point  of  departure  have  evolved 
numerous  though  similar  systems  of  recording  the  agrogeologic  data 
on  the  map.  The  geologic  formation  is  shown  by  the  color,  and  the 
soil  textures  by  sjmibols,  while  one  or  more  of  the  following  groups 
of  data  appear  and  may  be  shown :  topography  by  contours,  subter- 
ranean water  by  blue  figures,  location  of  borings  in  red  with  figures 
referring  to  tables,  amount  of  plant  food  elements  or  substances  by 
figures  or  hatchings,  varying  directions,  color,  or  nature  of  lines,  etc. 
The  nature  and  amount  of  the  data  shown  and  the  manner  of  repre- 
senting them  vary  a  great  deal.  Some  soilists,  to  use  a  term  proposed 
by  Coffey,5  advocate  and  use  superposable  maps  to  show  one  or  more 
groups  of  data,  thus  avoiding  unnecessary  confusion  on  the  main  map. 

Hazard0  proposed  a  scheme  of  classification  which  is  quite  as 
directly  connected  with  the  economic  factors  controlling  the  crops 
grown,  and  with  the  assessable  valuation  of  the  land,  as  with  the 
actual  or  potential  fertility  of  the  soil  itself.  There  are  several  classi- 
fications of  this  type,  involving  the  assessable  values  of  the  land. 


i  Rapport  BUT  Les  cartes  agronomiques,  Bull.  Min.  Agr.  France,  1893,  no.  8, 
pp.  956  73. 

•r>  Jour.  Amor.  Soc.  Agron.,  vol.  8  (1916),  p.  239. 

eLandw.  Jahrb.,  vol.  29  (1900),  pp.  805-911. 

Gregoire,  A.,  and  Halet,  F.,  Bull.  Inst.  Chem.  et  Bact.  Gembloux,  1906,  no.  75, 
pp.  1-43. 


1919]  Pendleton  :   A  Study  of  Soil  Types  373 

This  development  of  the  mapping  of  soils  as  an  outgrowth  of  areal 
geology  in  France  and  Germany  may  be  contrasted  with  the  develop- 
ment of  soil  classification  from  other  viewpoints,  such  as  that  of  the 
Russian  school.  In  Russia  there  is  not  the  predominance  of  residual 
and  shallow  soils  which  characterize  much  of  western  Europe  and 
which  in  France  especially  have  led  to  the  adoption  of  the  geologic 
basis  of  classification.  Dokoutchayev  and  Sibirtzev  have  been  the 
chief  proponents  of  a  classification  of  soils  based  upon  the  ' '  conception 
of  a  soil  as  a  natural  body  having  a  definite  genesis  and  a  distinct 
nature  of  its  own. '  'r 

The  genetic  conditions  of  the  formation  of  natural  soils  include 
the  following  variable  factors  which  cause  variation : 

(1)  The  petrographic  type  of  the  parent  rock;  (2)  the  nature  and  intensity  of 
the  processes  of  disintegration,  in  connection  with  the  local  climatic  and  topo- 
graphic conditions;  (3)  the  quantity  and  quality  of  that  complexity  of  organisms 
which  participate  in  the  formation  of  the  soil  and  incorporate  their  remains  in  it ; 
(-4)  the  nature  of  the  changes  to  which  these  remains  are  subjected  in  the  soil, 
under  the  local  climatic  conditions  and  physico-chemical  properties  of  the  soil 
medium;  (5)  the  mechanical  displacement  of  the  particles  of  the  soil,  provided 
this  displacement  does  not  destroy  the  fundamental  properties  of  the  soil,  its  geo- 
biological  character,  and  does  not  remove  the  soil  from  the  parent  rock;  and  (6) 
the  duration  of  the  processes  of  soil  formation. 

Upon  this  genetic  basis  there  has  been  developed  a  series  of  soil  zones, 
ranging  from  the  laterite  soils  in  the  tropics  to  the  tundras  in  the 
Arctic  regions.  The  outstanding  and  controlling  factor  in  the  scheme 
proposed  is  the  relation  of  these  zones  to  climate.  For  this  reason  the 
statement  usually  seen  is  that  climate  is  the  basis  of  the  classification.8 
There  are  nearly  as  many  groups  of  intra-zonal  and  azonal  soils  as 
of  those  belonging  to  the  zones  proper.  The  former  include  alkali, 
marshy,  alluvial,  and  other  soils. 

Hilgard,  while  actively  interested  in  the'  genetic  viewpoint  of  soil 
classification,  was  the  foremost  proponent  of  a  classification  upon 
the  basis  of  the  natural  vegetation  growing  upon  the  soil.9  This 
criterion  is  not  always  available,  though  some  groups  of  plants,  as  the 
alkali  tolerant  ones,  are  almost  invariably  present  where  the  condi- 


<Exp.  Sta.  Record,  vol.  12   (1900),  p.  704. 

See  also  Sibirtzev,  Cong.  Geol.  Intern.,  1897,  pp.  73-125;  abstract  in  Exp.  Sta. 
Eec.  vol.  12  (1900-01),  pp.  704-12,  807-18. 

Tulai'koff,  X.,  The  Genetic  Classification  of  Soils,  Jour.  Agr.  Sci.,  vol.  3  (1908), 
pp.  80-85. 

s  Coffey,  U.  S.  Bur.  Soils,  Bull.  85  (1912),  p.  32;  Jour.  Amer.  Soc.  Agron., 
vol.  8  (1916),  p.  241. 

9  Hilgard,  E.  W.,  Soils  (New  York,  Macmillan,  1906),  pp.  487-549. 


374  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

tions  are  unfavorable  for  the  less  resistant  plants.  Later  Hilgard 
and  Loughridge10  claimed  that  it  is  impracticable  to  attempt  "a  sat- 
isfactory tabular  classification  in  which  each  soil  shall  at  once  find  its 
pigeonhole  prepared  for  it  .  .  .  because  the  subject  matter  is  as  yet 
so  imperfectly  known. ' '  However,  this  does  not  dispute  the  justifica- 
tion for  making  classifications  for  specific  purposes  or  of  specific 
regions.  With  respect  to  this  point  there  seems  to  be  confusion.  The 
question  is  not  whether  soils  can  be  classified  at  all  or  not,  for  every 
observant  farmer  classifies  the  soil  with  which  he  is  familiar,  but 
whether  a  satisfactory  classification  is  possible  over  a  large  territory, 
where  soils  are  subject  to  the  varying  action  of  the  important  soil 
forming  agencies. 

Still  another  type  of  soil  mapping  is  that  of  Hall  and  Russell, 
which  is  given  in  their  admirable  Report  on  the  Agriculture  and  Soils 
of  Kent,  Surrey,  and  Sussex."11  In  this  district  the  soils  are  largely 
residual,  and  form  quite  distinct  groups,  depending  upon  the  parent 
geologic  formation.  These  groups  of  soils,  such  as  the  Clay-with- 
flints  and  the  Thanet  beds,  have  very  definite  agricultural  properties ; 
hence  the  treatment  of  all  phases  of  agriculture  upon  each  separate 
group  of  soils.  Hall  and  Russell12  present  an  excellent  discussion  of 
the  methods  of  soil  classification  and  the  interpretation  of  the  soil 
analyses  used  in  their  study.  Russell13  gives  a  very  similar  though 
briefer  treatment. 

There  are  other  more  or  less  specialized  classifications  that  have 
been  applied  to  local  conditions  and  problems.  As  an  example  may 
be  cited  Dicenty's  work  on  grape  soils.14 

Various  modifications  of  the  above  schemes  of  classifying  and  map- 
ping soils  are  found  in  general  texts  on  soils.15  Nowacki16  proposes  a 
curious  system,  Genera  et  Species  Terrarum.  It  is  in  Latin  terminology. 
The  genera  are  based  on  the  quality  of  the  soil,  whether  stony,  sandy, 
clayey,  peaty,  etc.,  and  the  species  are  dependent  upon  the  quantities 
of  organic  matter  and  clay. 


10  The  Classification  of  Soils,  Second  Intern.  Agrogeol.  Conf.,  Stockholm,  1910, 
p.  281. 

ii  London,  Bd.  Agr.  and  Fish.,  1911. 

12  Jour.  Agr.  Science,  vol.  4   (1911),  pp.  182-223. 

is  Soil  Conditions  and  Plant  Growth   (London,  Longmans,  1913),  pp.  132-48. 

14  Die  ampelogeologische  Kartierung.  First  Intern.  Agrogeol.  Cong.,  Budapest, 
1909,  pp.  257-71. 

'■"•  Ramann,  E.,  Bodenkunde,  Berlin,  Springer,  1911. 
Mitscherlich,  E.  A.,  Bodenkunde,  Berlin,  Parez,  1905. 
i« Praktwche  Bodenkunde  (Berlin,  1892),  pp.  130-80. 


1919]  Pendleton:   A  Study  of  Soil  Types  375 

Soil  Surveying  in  the  United  States. — In  a  brief  way,  it  has  been 
shown  how  there  arose  the  different  systems  of  soil  classification. 
Only  a  few  typical  systems  of  classifications,  and  something  of  the 
reasons  for  the  divergences,  have  been  mentioned.17  Probably  the  one 
agency  that  has  carried  on  the  most  extensive  soil  classification  and 
mapping  is  the  Bureau  of  Soils  of  the  United  States  Department  of 
Agriculture.  It  is  now  proposed  to  discuss  and  in  a  measure  criticize 
the  work  of  the  Bureau  of  Soils,  the  one  organization  that  has,  more 
than  any  other,  succeeded  in  applying  a  detailed  system  of  soil  classi- 
fication over  extensive  areas. 

The  problems  that  the  Bureau  had  to  face  during  its  early  exist- 
ence were  special  studies  of  the  soils  of  certain  crops,  especially  of  the 
tobacco  districts.18  Later  the  soil  utilization  work  of  the  Bureau  of 
Soils  was  transferred  to  other  branches  of  the  Department  of  Agri- 
culture, leaving  as  the  main  task  for  the  Bureau  the  systematic  classi- 
fication and  mapping  of  the  soils  of  the  United  States. 

Coffey19  has  so  well  discussed  the  present  day  conceptions  of  the 
bases  for  the  classification  of  soils,  that  it  does  not  seem  necessary  to 
repeat  any  portion  of  that  excellent  statement  here.  He  showed  that 
the  Bureau  of  Soils,  in  its  method  of  classifying  soils,  uses  a  combina- 
tion of  a  number  of  systems.  This  matter  is  dealt  with  more  in  detail 
in  an  article  b}r  Coffey,20  and  the  Report  of  the  Committee  on  Soil 
Classification  of  the  American  Society  of  Agronomy.21  The  question 
often  arises  as  to  the  validity  of  making  the  close  distinctions  regard- 
ing color,  texture,  geologic  origin,  etc.,  and  is  one  which  should  be 
dealt  with  in  order  to  render  less  empirical  the  nature  of  most  of  the 
criteria  which  are  used  at  present.  See  the  Report  of  the  Committee 
on  Soil  Classification  and  Mapping.22 

Because  of  different  views  regarding  soils  and  soil  fertility  from 
those  held  by  the  Bureau  of  Soils,  the  Illinois  Agricultural  Experi- 
ment Station  has  undertaken  a  soil  survey  and  classification,  under  the 
direction  of  Dr.  C.  G.  Hopkins,  which  is  independent  of  the  Bureau 


17  See  Coffey's  excellent  treatment  of  the  soil  survey  work  in  this  country. 
The  Development  of  Soil  Survey  Work  in  the  United  States  with  a  Brief  Reference 
to  Foreign  Countries,  Proc.  Amer.  Soc.  Agron.,  vol.  3  (1911),  pp.  115-29. 

is  Whitney,  Extension  and  Practical  Application  of  Soil  Surveys,  Off.  Exp. 
Sta.,  Bull.  142  (1903),  pp.  111-12;  The  Purpose  of  a  Soil  Survey,  U.  S.  Dept. 
Agr.,  Yearbook,  1901,  pp.  117-32. 

is  A  Study  of  the  Soils  of  the  United  States,  U.  S.  Bur.  Soils,  Bull.  85  (1912), 
pp.  24-38. 

20  Jour.  Amer.  Soc.  Agron.,  vol.  8   (1916),  pp.  239-43. 
2i  Ibid.,  vol.  6  (1914),  pp.  284-88. 
22  Ibid.,  vol.  8  (1916),  pp.  387-90. 


376  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

of  Soils,  and  differs  from  its  methods  in  a  number  of  ways.  Since  the 
soils  of  Illinois  are  of  a  much  narrower  range  of  variation  than  are 
those  of  the  whole  of  the  United  States,  the  system  of  classification 
for  the  state  need  not  be  so  elaborate.  The  soils  are  divided  accord- 
ingly as  they  have  been  glaciated  or  not,  and  if  glaciated,  in  what  glaci- 
ation  period.  They  are  further  divided  according  to  color,  topogra- 
phy, and  texture  of  soil  and  subsoil.23  Correlation  of  the  types  of 
soil  mapped  in  the  various  areas,  one  of  the  greatest  sources  of  criti- 
cism of  the  Bureau  of  Soils  survey  methods,  is  more  easily  handled 
in  the  Illinois  work,  since  it  is  possible  for  the  one  in  charge  of  the 
work  to  pass  personally,  while  in  the  field,  upon  all  correlation  and 
the  establishment  of  all  new  types.  It  is  insisted  that  the  field  men 
map  accurately  and  in  sufficient  detail.  This  insures  the  accuracy  of 
the  maps  as  regards  the  standards  adopted,  the  information  is  specific, 
and  the  local  users  of  the  maps  are  not  misled.24  In  connection  with 
the  field  classification  and  mapping,  pot  and  plot  cultures  are  carried 
on,  not  so  much  to  test  the  relative  fertility  of  the  untreated  soils,  but 
to  determine  the  effects  of  the  application  of  various  sorts  and  quanti- 
ties of  fertilizers.  Hopkins,25  to  show  the  differences  in  detail  between 
the  U.  S.  Bureau  of  Soils  mapping  and  that  of  the  Illinois  Experi- 
ment Station,  compares  a  U.  S.  Bureau  survey  of  1902  with  a  state 
survey  published  in  1911.  This  is  not  entirely  fair,  because  with  the 
increase  of  field  knowledge  of  soils  gained  by  them  and  the  realiza- 
tion of  the  need  of  representing  the  soils  in  more  detail,  a  survey 
made  by  the  Bureau  in  1911  would  almost  certainly  show  much  more 
detail  and  show  it  with  greater  accuracy  than  the  maps  made  in  the 
early  period  of  the  work.  This  point  may  be  strengthened  by  the 
notes  given  below  on  the  comparison  of  a  portion  of  an  early  survey 
made  in  southern  California  by  the  Bureau  of  Soils  with  a  recent 
survey  of  the  same  soils  made  by  the  Bureau  and  the  University  of 
California  working  in  cooperation. 

PLAN  OF  THE  PRESENT  STUDY 

The  present  study  is  an  attempt  to  see  if  certain  soil  types  mapped 
as  the  same  from  different  areas  in  the  state  of  California,  and  judged 
to  be  the  same  by  the  criteria  used  by  the  Bureau  of  Soils,  are  the 


28  Hopkins,   Soil    Fertility  and   Permanent   Agriculture    (Boston,   Ginn,   1910) 
pp.  54-57. 

24  Ibid.,  ]>.  115. 

28  Jbid.,  pp.  114-15. 


1919]  Pendleton:   A  Study  of  Soil  Types  377 

same  or  similar  when  examined  from  the  laboratory  standpoint.  For 
example,  we  may  take  the  Hanford  fine  sandy  loam,  which  is  one  of 
the  types  that  has  been  used  in  the  present  study.  According  to  the 
criteria  of  color,  mode  of  formation,  origin  (as  judged  by  the  presence 
of  mica),  nature  of  subsoil,  texture,  etc.,  this  soil  has  been  found  and 
mapped  in  a  number  of  areas  that  have  been  mapped  in  this  state. 
But  will  these  various  bodies  of  soil,  from  widely  separated  portions 
of  the  state,  when  judged  by  laboratory  and  greenhouse  studies  on 
samples  as  nearly  representative  as  possible,  appear  to  be  the  same  or 
similar  ? 

The  types  selected  for  such  a  study  as  this  should  fulfil  the  follow- 
ing conditions :  first,  they  should  have  at  least  a  reasonably  wide  dis- 
tribution in  the  state  so  as  to  have  been  mapped  in  a  number  of  differ- 
ent soil  survey  areas ;  and  second,  the  several  types  should  be  repre- 
sentative of  different  classes  of  soils  (clays,  loams,  sandy  loams,  etc.), 
so  that  contrasts  could  be  obtained  between  the  types. 

In  the  collection  of  samples  it  was  aimed  to  obtain  representative 
samples  from  each  of  a  number  of  bodies  of  soil  of  the  types  selected ; 
not  to  obtain  possible  variations  from  the  ideal  in  any  one  body.  In 
the  laboratory  the  soils  were  compared  with  regard  to  their  physical 
composition  in  the  surface  horizon,  to  their  chemical  composition  in 
three  horizons,  and  to  their  relative  bacteriological  activities.  In  the 
greenhouse  the  soils  (surface  horizon  only)  were  placed  in  large  pots 
and  their  comparative  ability  to  produce  various  crops  was  studied. 

No  claim  is  made  that  these  criteria  should  be  the  ones  used  in 
determining  the  systematic  classification  of  soils  or  in  determining 
the  relative  fertility  of  the  soils.  They  were  merely  used  to  determine 
how  nearly  the  soils  classed  under  a  given  type  name  agree  from  the 
standpoints  named. 

DISCUSSION  OF  RESULTS 

The  bacteriological  and  chemical  determinations  were  run  in  dupli- 
cate so  that  the  figures  presented  are  averages.  It  is  considered  that 
this  gives  fairer  figures  for  comparison,  especially  since  the  determina- 
tions were  run  on  separate  samples,  and  not  on  aliquots  of  a  single 
solution  from  a  single  sample. 

There  is  a  very  important  factor  which  should  always  be  kept  in 
mind  especially  when  considering  the  bacteriological  and  greenhouse 
comparisons.     This  is  the  factor  of  the  probable  error.     Though  the 


378  University  of  California  "Publications  in  Agricultural  Sciences        [Vol.  3 

advisability  of  judging  all  results  in  the  light  of  the  probable  error 
is  admitted,  no  attempt  has  been  made  to  apply  this  factor  to  the 
results  reported  in  this  paper.  As  the  result  of  the  effect  which  such 
a  factor  might  have  upon  the  results  of  bacteriological  determina- 
tions carried  on  only  in  duplicate,  or  upon  the  results  of  greenhouse 
work  done  in  triplicate,  one  hesitates  to  draw  conclusions,  especially 
those  based  upon  minor  variations.  Hence  in  this  work  only  the  more 
marked  results  will  be  considered  of  significance. 

When  planning  the  work  it  was  thought  that  three  or  four  samples 
of  a  type  would  be  enough  to  show  whether  or  not  a  given  type  was 
approximately  uniform,  or  widely  variable,  and  as  to  whether  the 
types  were  similar  to  one  another,  or  quite  dissimilar.  But  it  now 
seems,  after  comparing  the  determinations  run  on  the  larger  number 
of  samples  of  the  Hanford  and  San  Joaquin  types,  9  and  8  respec- 
tively, with  the  determinations  run  on  the  Altamont  and  Diablo  types, 
of  which  there  were  a  much  smaller  number  of  samples,  3  and  4 
respectively,  that  the  larger  series  gives  a  much  better  insight  into  the 
variations  of  a  given  type  and  affords  a  much  better  basis  for  con- 
clusions. 

Hence,  as  regards  the  laboratory  work  thus  far  carried  out,  the 
emphasis  has  been  placed  upon  the  Hanford  fine  sandy  loam  and  the 
San  Joaquin  sandy  loam.  Determinations  have  not  been  completed 
on  the  Altamont  and  Diablo  series  to  the  extent  that  they  have  on  the 
former  two. 

It  is  of  no  little  significance  that  the  Hanford  fine  sandy  loam  and 
the  San  Joaquin  sandy  loam  are  very  widely  contrasted  soils  agricul- 
turally. The  Hanford  is  typical  of  good  recent  alluvial  soil  in  this 
state ;  while  the  San  Joaquin  is  typical  of  wide  expanses  of  ' '  old  valley 
filling"  soils  that  are  considered  poor  as  regards  crop  producing 
power  and  are  underlain  by  compact  iron-cemented  hardpan.  Conse- 
quently, the  results  of  comparing  soils  so  different  from  an  agricul- 
tural point  of  view,  and  so  radically  different  as  regards  soil  survey 
criteria  (though  the  textures  are  quite  similar)  will  be  of  considerable 
interest.  They  are  of  greater  interest  than  the  comparisons  between 
the  Diablo  and  Altamont  soils,  as  the  latter  are  quite  similar  in  agri- 
cultural value  and  use,  as  well  as  in  field  appearances.  Between  the 
Diablo  or  Altamont  and  the  Hanford  or  San  Joaquin  one  cannot 
judge  as  closely  regarding  variations,  for  the  soils  are  so  radically 
different.  On  the  other  hand,  one  can  compare  the  soils  of  the  heavy 
and  light  types  to  see  to  what  extent  the  chemical  and  bacteriological 
results  differ  as  compared  with  the  physical  results. 


02.5  0.5      /.        Z.       4       9.       16.     32.    64.  Grits. 


Size  of  Particles  nam- 

Fig.    1.     Graph   showing   the   results   of   the    Hilgard   elutriator    method    of 
mechanical  analysis  on  the  four  samples  of  Diablo  clay  adobe. 


380 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Mechanical  Analysis 

Hilgarcl  Elutriator  Method. — That  there  is  a  wide  variation  be- 
tween the  samples  is  apparent  (figs.  1-4).  In  fact,  there  is  about 
as  wide  a  range  of  differences  among  the  samples  of  the  Hanford 

% 

45 


40 


35 


30 


20 


i:. 


10 


j 

A 

i 

1 

// 

// 

,   / 

\ 

// 

\ 
\ 

1 

\ 

1 

v 

\ 

i\ 
\ 

\ 

\ 

\ 

\     \ 

\     \ 

\\ 

/ 

\   \ 

/ 

/ 
/ 
/ 

v. 

*'</' 
/£—— 

N, 

N 

/' 

\ 
\ 

/ 

/ 

\ 

r                         , 

\ 
\ 

\ 

32 


64  m  m. 


Pig.    2.     Graph    showing   the   results    of   the   Hilgard    elutriator    method    of 
mechanical  analysis  on  the  three  samples  of  Altamont  clay  loam. 


fine  sandy  loam  and  among  those  of  the  San  Joaquin  sandy  loam  as 
between  the  two  types.  The  most  outstanding  differences  are  where 
they  ought  to  be,  to  show  the  differences  that  the  type  names  presup- 
pose, i.e.,  in  the  "coarse  sand"  (64  mm.)  and  the  "grits."  The  sam- 
ples  of  the  San  Joaquin  sandy  loam  average  a  larger  proportion  of 
each  of  these  separates  than  do  the  Hanford  fine  sandy  loam  soils. 


1919] 


Pendleton :   A  Study  of  Soil  Types 


381 


In  the  Hanford,  no.  14  is  notably  heavier  than  the  others,  as  shown 
by  its  silt  content,  which  is  nearly  half  again  as  great  as  that  of  the 
next  highest  sample. 

The  gravel  content   (sizes  above  2  mm.)   is  interesting  in  its  uni- 
formity.    In  the  San  Joaquin  soils  the  two  samples  above  1%   are 


:lqy     Q25     0.5        I  2.        4-         8         16       32      64-    Grits 

Size  of  Particles.  mm 

Fig.    3.     Graph   showing   the    results    of   the   Hilgard    elutriator    method    of 
mechanical  analysis  on  the  eight  samples  of  San  Joaquin  sandy  loam. 


nos.  11  and  26.  The  material  in  the  latter  soil  is  composed  almost 
wholly  of  iron  concretions,  leaving  sample  no.  11  as  the  only  soil  with 
more  than  1%  actual  gravel.  In  the  Hanford  samples  none  were 
found  to  have  more  than  1.5%  gravel. 

The  Hilgard  method  does  not  include  any  precise  subdivision  of 
the  soils  into  groups  or  classes  according  to  texture.  Dr.  Hilgard  was 
not  in  favor  of  making  the  fine   distinctions  in  texture  that  other 


382 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


investigators  have  emphasized.  But  if  there  were  such  a  scheme, 
similar  to  that  which  the  Bureau  of  Soils  uses,26  it  would  be  an  easy 
matter  to  compare  the  results  obtained  through  the  use  of  the  elutri- 
ator,  and  determine  whether  or  not  the  soils  examined  belong  to  a 
given  class.     The  simple  comparison  of  the  quantities,   in  different 


40% 


0^5~    0.5       1.0       2.0      4.0      8.0       16.  32.      64-.   Grits. 

Size  of  Particles.  mm. 

Fig.    4.     Graph    showing   the   results    of   the    Hilgard  elutriator    method    of 

mechanical  analysis  on  the  nine  samples  of  Ilanford  fine  sandy  loam. 


samples,  of  any  given  separate  or  separates  is  not  absolute.  For  it 
must  be  realized  that  the  conception  of  a  soil  class  includes  a  certain 
range  in  the  quantities  of  particles  of  the  various  sizes.  This  must 
be  so  since  soils  are  ordinarily  grouped  into  but  ten  or  twelve  class 
textures,  while  there  exist  among  soils  those  with  all  gradations  in 
the  quantities  of  particles  of  the  various  sizes. 


28  Instructions    to    Field    Parties,   U.    S.    Bur.    Soils,    Bull.    1914,    p.    75;    ibid., 
Bull.  85  (11)12;,  p.  28. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


383 


And  because  the  ranges  in  the  sizes  of  the  soil  particles  separated 
by  the  Bureau  of  Soils  method  cut  across  those  of  the  Hilgard 
method,  it  is  impossible  to  regroup  the  results  so  that  the  Bureau  of 
Soils  grouping  into  textures  may  be  applied.  But  without  any  such 
scheme,  desirable  as  it  may  be,  it  has  been  pointed  out  that  there  is 
clearly  apparent  a  rather  wide  variation  in  the  analyses  of  the  several 
samples  of  a  type.  All  the  soils  representative  of  a  given  type  are  by 
no  means  closely  similar  to  one  another. 

Table  1 — Comparison  of  Textures 

Texture    determined    by 


Texture  as  judged  in  the  field 

mechanical   analysis 

*1 

Diablo  clay  adobe 

Clay 

2 

Diablo  clay  adobe 

Clay 

3 

Altamont  clay  loam 

*Silty  clay 

4 

Altamont  clay  loam 

Clay  loam   (sandy) 

5 

Diablo  clay  adobe 

Clay 

6 

Diablo  clay  adobe 

Clay 

7 

Altamont  clay  loam 

Clay  loam  (heavy) 

10 

San  Joaquin  sandy  loam 

*Fine  sandy  loam 

11 

San  Joaquin  sandy  loam 

Sandy  loam  (heavy) 

12 

San  Joaquin  sandy  loam 

*Fine  sandy  loam 

13 

San  Joaquin  sandy  loam 

*Fine  sandy  loam   (heavy) 

14 

Hanford  fine  sandy  loam 

Fine  sandy  loam   (loam) 

15 

Hanf  ord  fine  sandy  loam 

Fine  sandy  loam 

16 

Hanford  fine  sandy  loam 

*  Sandy  loam 

17 

San  Joaquin  sandy  loam 

Sandy  loam 

18 

San  Joaquin  sandy  loam 

Sandy  loam 

19 

Hanford  fine  sandy  loam 

* Sandy  loam    (heavy) 

20 

Hanford  fine  sandy  loam 

Fine  sandy  loam 

21 

Hanford  fine  sandy  loam 

Sandy  loam 

22 

Hanford  fine  sandy  loam 

Fine  sandy  loam 

23 

Hanford  fine  sandy  loam 

Fine  sandy  loam 

24 

Hanford  fine  sandy  loam 

Fine  sandy  loam 

25 

Hanford  fine  sandy  loam 

Fine  sandy  loam 

26 

San  Joaquin  sandy  loam 

Sandy  loam 

Note. — Textures  not  judged  correctly  in  the  field. 


Mechanical  Analysis  by  the  Bureau  of  Soils  Method. — Among  the 
other  determinations  made  by  the  Division  of  Soil  Technology  on  the 
surface  horizons  of  the  twenty-four  soils  used  in  this  investigation 
was  that  of  making  the  mechanical  analysis.  The  tables  show  the 
percentages  of  the  several  separates.  In  all  cases  the  figures  represent 
averages  of  duplicate  determinations  and  in  some  cases  the  averages 
of  quadruplicate  determinations.  With  this  method,  as  well  as  with 
the  Hilgard  elutriator,  there  are  shown  wide  variations  between  the 


384  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


.005   .005     .05       JO       .25        .5         1.0 
mm.     -.05    -JO      -£5     -.5       -/.Q      -2.0 

miD.      mm.      mm.      mm.      mm.      mm. 

Pig.    5.     Graph    showing    the    results    of    the    Bureau    of    Soils    method    of 
mechanical  analysis  on  the  four  samples  of  Diablo  clay  adobe. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


38: 


samples  of  a  given  type.  But  the  graphs  of  the  percentages  (figs. 
5-8),  determined  by  the  Bureau  of  Soils  method  for  the  several  types 
are  not  as  closely  similar  as  the  graphs  of  the  elutriator  results  for 
the  same  types.  That  is,  using  the  Bureau  of  Soils  method,  the  graph 
of  the  Hanford  fine  sandy  loam  does  not  resemble  th,at  of  the  San 
Joaquin  sandy  loam  as  much  as  do  the  graphs  of  the  results  made 


Fig.    6. 


.005         .005-.05         .05-.  10  .10-. 25  .25-. 5  .5-1.0  1.-2. 

Graph    showing    the    results    of    the    Bureau    of    Soils    method    of 


mechanical  analysis  on  the  three  samples  of  Altamont  clay  loam. 


upon  the  same  soils  by  the  Hilgard  elutriator  method.  This  would 
lead  one  to  believe  that  the  Bureau  of  Soils  method  of  mechanical 
analysis  is  the  better  suited  for  separating  soils  into  groups;  even 
though  these  soils  which  were  classified  in  the  field  according  to  the 
differences  which  are  the  more  prominent  would  be  expected  to  show 
greater  differentiations  when  examined  by  the  Bureau  of  Soils  labora- 
tory methods. 


386 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Comparison  of  Textures. — Table  1  gives  the  texture  as  shown  on 
the  soil  survey  map  of  the  locality,  as  well  as  the  results  of  the  labora- 
tory check.    This  texture  as  given  on  the  map  was  also  judged  by  me 


.005   .005      .05       .10        25 
-.05      -./O       -Z5      -.5 
Size  of  Particles. 

Pig.    7.     Graph    showing    the    results    of    the    Bureau    of    Soils    method    of 
mechanical  analysis  on  the  eight  samples  of  San  Joaquin  sandy  loam. 


in  the  field  to  be  more  or  less  true  to  the  type  as  mapped.  I  say  more 
or  less  true,  for  the  field  notes,  as  given  in  appendix  B,  show  that  in 
several  cases  I  was  unable  to  obtain  in  the  locality  what  I  believed  to 


1919] 


Pendleton:   A  Study  of  Soil  Types 


387 


be  a  sample  of  the  soil  thoroughly  typical  of  the  class  and  type  in 
question.  Sample  no.  3  had  a  large  lime  content  which  I  thought 
might  more  or  less  obscure  the  texture.  ''Slightly  heavy,  and  barely 
enough  sand  for  a  sandy  loam"  is  the  comment  on  sample  12,  while 
"a  heavy  sandy  loam,  approaching  a  loam"  is  found  in  the  notes  on 
sample  13.  The  second  column  of  the  table  shows  the  class  sub- 
divisions into  which  the  soils  were  placed  according  to  the  mechanical 
analysis.  The  words  in  parenthesis  show  modifying  conditions  but 
do  not  indicate  a  change  in  the  class.  In  considering  the  class  groups 
such  as  sandy  loam,  fine  sandy  loam,  etc.,  it  should  be  remembered 
that  though  the  groups  are  rather  broad,  the  limits  are  arbitrary 
and  quite  sharp.  So  the  results  of  a  mechanical  analysis  may  place 
a  soil  in  the  sandy  loam  class  if  25%  or  more  is  fine  gravel,  coarse  and 
medium  sand,  while  if  less  than  25%  be  present  the  soil  belongs  to  the 
fine  sandy  loam  class,  providing  at  the  same  time  the  amounts  of  silt, 
clay,  and  fine  sand  are  within  the  specified  limits.  The  two  soils  may 
be  a  great  deal  alike  in  texture  though  placed  in  different  classes. 
The  failure  of  my  judgment  regarding  the  texture  shows  one  of  the 
difficulties  that  the  field  man  is  continually  facing.  And  his  failure 
to  judge  textures  correctly  is  one  of  the  causes  of  criticism  of  soil 
survey  work. 


Table  2 — Mechanical  Analyses, 

HlLGARD   ELUTRIATOR   METHOD 

Diablo  Clay  Adobe 

Separates 

Samples 

r 

Diameter, 
mm. 

Velocity, 

mm.  per 

second 

Name 

1-A 

% 

2-A 

% 

5-A 

% 

6-A 

% 

Clay 

.01 

0.25 

44.16 

35.81 

44.97 

64.63 

Fine  silt 

.01  -.016 

0.25 

23.91 

34.08 

25.57 

25.13 

Medium   silt 

.016-.025 

0.5 

5.97 

7.37 

4.14 

1.03 

.025-.036 

1 

8.10 

9.09 

5.28 

1.83 

Coarse  silt 

.036-.047 

2 

7.77 

7.47 

5.45 

1.99 

.047-.072 

4 

6.05 

4.09 

6.18 

2.13 

Fine  sand 

.072-.12 

8 

3.28 

1.33 

5.81 

2.07 

.12  -.16 

16 

0.48 

0.43 

1.73 

0.90 

Medium  sand 

.16  -.30 

32 

0.08 

0.21 

0.38 

0.21 

Coarse  sand 

.30  -.50 

64 

0.18 

0.11 

0.49 

0.11 

Total  weight 

of  separates,  gm. 

19.18 

19.62 

19.30 

19.68 

Weight   of  original  sample,  gm. 

18.83 

18.88 

18.66 

18.16 

Grits,  % 

0.5-2.0  mm. 

0.26 

0.29 

0.57 

0.10 

Hygroscopic 

moisture,    % 

6.20 

5.93 

7.18 

10.12 

University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


.005     .005       .05        JU         .25         .5  1.0  mm 

-.05 ,      -.1.0        -Z5        -.5         -1.0         2.0  mm. 

Size  of  Particles 

Pig.    8.     Graph    showing    the    results    of    the    Bureau    of    Soils    method    of 
mechanical  analysis  on  the  nine  samples  of   llnnford  fine  sandy  loam. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


389 


Table  3 — Mechanical  Analyses,  Hilgard  Elutriator  Method 

Allamont  Clay  Loam 
Separates 


' 

Diameter 
mm. 

Velocity 
mm.  per 
second 

A 

Name 

3 -A 

% 

4-A 

% 

7-A 
% 

Clay 

.01 

0.25 

28.48 

26.41 

22.65 

Fine  silt 

.01  -.016 

0.25 

43.42 

17.73 

41.18 

Medium  silt 

.016-.025 

0.5 

2.96 

2.39 

4.67 

.025-.036 

1 

4.37 

4.82 

8.51 

Coarse  silt 

.036-.047 

2 

4.95 

4.89 

6.01 

.047-.072 

4 

5.52 

7.52 

7.90 

Fine  sand 

.072-.12 

8 

5.14 

8.83 

5.54 

.12  -.16 

16 

3.89 

13.61 

1.98 

Medium  sand 

.16  -.30 

32 

0.88 

10.40 

0.95 

Coarse  sand 

.30  -.50 

64 

0.21 

3.39 

0.61 

Total  weights 

of  separates, 

gm. 

18.71 

19.54 

20.96 

Weight  of  ori 

ginal  sample, 

gm. 

18.50 

19.16 

19.21 

Grits,  %         0 

.5-2.0  mm. 

3.98 

8.09 

1.63 

Hygroscopic  moisture,  % 

8.08 

4.37 

4.09 

Table  4 — Mechanical  Analyses,  Hilgard  Elutriator  Method 
San  Joaquin  Sandy  Loam 


Separates 

Sampl 

es 

Diameter 
t       mm. 

Velocity, 

mm. 

per 

second 

Name 

10-A 

% 

ll-A 

% 

12-A 

% 

13-A 

% 

17-A 

% 

18-A 

% 

21-A 

% 

2  6- A 

% 

Clay 

.01 

0.25 

11.14 

15.46 

8.99 

10.75 

10.53 

8.72 

8.35 

16.64 

Fine  silt 

.01  -.016 

0.25 

20.24 

31.88 

26.57 

24.04 

16.20 

18.56 

14.73 

20.78 

Medium 

silt 

.016-.025 

0.5 

1.44 

2.73 

2'.31 

4.64 

1.81 

3.06 

3.54 

3.83 

.025-.036 

1 

6.54 

9.11 

1.33 

9.86 

5.89 

6.93 

6.98 

9.24 

Coarse  silt 

.036-.047 

2 

8.36 

10.23 

1.19 

9.59 

5.82 

6.90 

7.10 

7.09 

.047-.072 

4 

9.50 

8.41 

10.14 

10.05 

8.46 

8.45 

7.67 

8.89 

Fine  sand 

.072-.12 

8 

10.66 

7.47 

10.72' 

10.92 

12.04 

9.72 

12.86 

5.77 

.12  -.16 

16 

10.30 

5.97 

10.88 

16.14 

13.43 

10.56 

13.53 

3.85 

Medium 

sand 

.16  -.30 

32 

14.69 

6.91 

11.75 

1.96 

19.21 

16.59 

3  3.05 

0.86 

Coarse  san 

d  .30  -.50 

64 

7.11 

1.32 

3.54 

2.12 

6.60 

10.50 

12.14 

23.04 

Total  weight  of  separates,  gm. 

20.02' 

20.44 

19.99 

20.10 

20.38 

20.06 

20.33 

20.14 

Weight  of 

original  sample,  gm. 

19.80 

19.51 

19.72 

19.76 

19.85 

19.86 

19.85 

19.69 

Grits,    % 

0.5-2.0  mm. 

16.70 

23.54 

8.84 

8.10 

23.12 

32.00 

28.50 

36.00 

Hygroscop 

>ic   moisture 

,    % 

0.98 

2.48 

1.38 

1.22 

0.75 

0.70 

0.75 

1.57 

Note. — All  weighings  made  on  the  water  free  basis. 


390 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table  5 — Mechanical  Analyses,  Hilgard  Elutriator  Method 


Han  ford  Fine  Sandy  Loam 


Separates 


Name 
Clay 

Fine   silt 
Medium 


silt 


Coarse   silt 

Fine    sand 

Medium  sand 
Coarse  sand 


Velocity, 
mm. 
Diameter     per 
mm.      second 

0.25 

0.25 

0.5 

1 

2 

4 

8 
16 
32 
64 


.01 
.01  -.016 
.016-.025 
.025-.036 
.036-.047 
.047-.072 
.072-12 
.12  -.16 
.16-  .30 
.30-  .50 


Total  weight  of  separates,  gm. 
Weight  of  original  sample,  gm. 
Grits,    %  0.5-2.0 

Hygroscopic    moisture,    % 


14- A 

% 

12.89 

37.25 

4.19 

8.63 

7.95 

6.23 

5.26 

7.15 

8.81 

1.43 

20.19 

19.46 

4.12' 

2.73 


Samples 


15-A 

% 

8.16 

19.39 

3.05 

5.04 

6.57 

10.23 

12.31 

13.93 

15.29 

6.02' 

20.23 

19.90 

13.23 

0.49 


16-A 

% 

11.97 

24.61 

3.22 

5.06 

5.99 

7.27 

8.57 

9.76 

16.05 

7.51 

20.53 

19.69 

25.47 

1.54 


19-A 

% 

11.09 

5.95 

1.67 

5.27 

7.14 

12.76 

17.79 

12.00 

24.20 

2.13 

20.08 

19.82 

7.85 

0.89 


20-A 

% 

10.55 

22.09 

6.40 

8.40 

7.68 

9.93 

10.48 

12.29 

10.03 

2.70 

20.27 

19.73 

6.71 

1.34 


22-A       23-A 


7.97 

14.15 

3.15 

5.29 

6.47 

11.30 

17.15 

17.39 

14.87 

2.27 

20.06 

19.81 

3.07 

0.94 


8.68 

22.57 

5.90 

6.89 

10.53 

13.03 

12.71 

7.94 

9.88 

1.85 

20.30 

19.78 

7.24 

1.10 


2  4- A 

% 

6.47 

11.11 

1.20 

5.08 

7.48 

13.91 

19.27 

21.56 

12.36 

1.50 

20.26 

19.83 

6.85 

0.84 


25-A 

% 

6.65 

14.54 

1.59 

6.36 

7.91 
12.64 
18.11 

9.55 
19.15 

3.50 
19.18 
19.78 

3.83 

1.10 


Table  6 — Mechanical  Analyses,  Bureau  of  Soils  Method 
Diablo  Clay  Adobe 


Separates 

Sampb 

3S 

Name 

Diameter 
mm. 

l-A 

2-A 

% 

5-A 

% 

6-A 

% 

Clay 

.005 

44.81 

44.44 

45.67 

56.01 

Silt 

.005-  .05 

32.00 

42.51 

23.01 

14.28 

Very  fine  sand 

.05  -  .10 

19.61 

11.35 

21.58 

25.58 

Fine  sand 

.10  -  .25 

1.36 

1.33 

4.81 

2.10 

Medium  sand 

.25  -  .5 

0.26 

0.69 

0.95 

2.05 

Coarse  sand 

.5     -1.0 

0.58 

0.20 

1.56 

0.00 

Fine  gravel 

1.0     -2.0 

0.03 

0.02 

0.04 

0.00 

Note. — Determinations  made  by  the  Division  of  Soil  Technology. 


Table  7 — Mechanical  Analyses,  Bureau  of  Soils  Method 


Altamont  Clay  Loam 


Separates 

Samples 

Name 

Diameter 
mm. 

3-A 

% 

4-A 

% 

7-A 
% 

Clav 

.005 

33.19 

26.50 

31.84 

Silt 

.005-  .05 

31.76 

17.35 

37.40 

Very  fine  sand 

.05  -  .10 

22.81 

39.15 

24.70 

Fine  sand 

.10  -  .25 

8.97 

6.08 

3.27 

Medium  sand 

.25  -  .5 

1.99 

7.78 

0.92 

Coarse   sand 

.5     -1.0    " 

1.74 

3.06 

0.55 

Fine  gravel 

1.0     -2.0 

1.01 

1.22 

0.22 

NOTE. — Determinations   made  by  the   Division   of   Soil   Technology. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


391 


Table  8 — Mechanical  Analyses,  Bureau  of 

Soils  Method 

San  Joaquin  Sandy 

Loam 

Separal 

es 

Samples 

A 

Name 

^ 
Diameter 
mm. 

10-A 

% 

ll-A 

% 

12-A 

% 

13-A 

% 

17-A 

% 

18-A 

% 

21-A 

% 

2  6- A 

% 

Clay 

.005 

10.78 

15.77 

16.16 

16.94 

11.77 

10.49 

8.28 

17.38 

Silt 

.005-  .05 

21.60 

35.97 

25.04 

22.70 

15.97 

2'6.74 

17.70 

18.17 

Very  fine  sand 

.05  -  .10 

28.07 

18.53 

27.42 

47.01 

20.42 

12.02' 

15.92 

13.84 

Fine  sand 

.10  -  .25 

19.96 

2.66 

17.07 

3.99 

22.57 

16.61 

21.27 

10.26 

Medium  sand 

.25  -  .5 

9.20 

6.96 

5.80 

4.69 

10.75 

13.85 

13.57 

14.72 

Coarse  sand 

.5     -1.0 

9.08 

8.51 

6.52 

2.96 

13.81 

16.52 

21.41 

24.26 

Fine  gravel 

1.0     -2.0 

1.34 

12.52' 

2.15 

1.81 

3.13 

4.07 

2.07 

2.02 

Note. — Determinations  made  by  the  Di 

vision  of 

Soil  Technology. 

Table  9 — Mechanical  Analyses,  Bureau  of  Soils  Method 
Ranford  Fine  Sandy  Loam 


Separates 

A 

Samples 

A 

f                                                                                                 *\ 

Diameter 
Name                              mm. 

14-A 

% 

15-A 

% 

16- A 

% 

19- A 

% 

20-A 

% 

22-A 

% 

23-A 

% 

2  4- A 

% 

25-A 

% 

Clay                           .005 

14.10 

12.08 

16.84 

15.28 

15.95 

7.79 

10.61 

9.83 

7.60 

Silt                             .005-  .05 

39.25 

22.42 

16.16 

15.03 

32.90 

22.70 

24.38 

11.42 

12.90 

Very  fine  sand          .05  -  .10 

22.66 

37.12 

16.46 

32.87 

22.58 

36.15 

38.73 

42.05 

67.37 

Fine   sand                 .10  -  .25 

17.54 

6.51 

17.32 

8.13 

18.20 

27.78 

16.51 

28.73 

5.88 

Medium  sand           .25  -  .5 

4.71 

11.40 

11.70 

15.42 

4.97 

4.21 

4.66 

4.27 

3.47 

Coarse  sand             .5     -1.0 

1.99 

8.49 

15.54 

9.27 

3.07 

1.47 

3.28 

3.01 

1.27- 

Fine   gravel           1.0     -2.0 

0.13 

1.91 

5.27 

3.63 

0.20 

0.20 

1.48 

1.02 

1.02 

Note. — Determinations  made 

by  the  Division  i 

af  Soil  Technology. 

Moisture  Equivalent. — The  moisture  equivalents  of  the  surface 
horizon  samples  were  determined  by  the  Division  of  Soil  Technology 
(table  10,  and  figs.  9,  10).  The  different  types  gave  quite  distinct 
averages,  though  there  was  considerable  variation  within  the  type. 
The  Diablo  clay  adobe  varied  from  37%  to  57%,  with  an  average  of 
47%.  The  Altamont  clay  loam  varied  from  22%  to  37%,  with  28% 
as  an  average.  The  San  Joaquin  sandy  loam  varied  from  7%  to 
15%,  with  the  average  of  11%.  The  Hanford  fine  sandy  loam  varied 
from  11%  to  25%,  with  15%  as  the  average.  These  figures  show 
that  as  a  whole  the  moisture  equivalents  of  the  several  types  are 
distinct,  though  there  is  the  usual  overlapping  in  some  cases.  The 
samples  of  a  given  type  are  in  many  instances  closely  similar,  though 
not  always  or  even  usually  so. 


392  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


60 


55 


50 


45 


10 


30 


25 


20 


15 


10 


1 

/ 

1 

\ 

\ 

\ 

\ 
\ 
\ 

/ 
/ 

/ 
/ 

Moisture 
Equivalent 


Hygro. 

Coef. 


35 


;;<> 


20 


10 


\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 
\ 

^- 

Moisture 
Equivalent 


Hygro. 
Coef. 


12  5  6  Soils  3  4  7  Soils 

Fig.  9.  Graph  showing  the  results  of  the  determination  of  the  moisture 
equivalent  and  of  the  hygroscopic  coefficient  on  the  four  samples  of  Diablo 
clay  adobe  and  the   three   samples   of   Altamont  clay  loam. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


393 


Table  10 — Moisture  Equivalent 


Diablo   Clay 

A 

Adobe 

Altamont  Clay  Loam 

San 
No. 

Joaquin 
Loam 

A 

Sandy 

Hanford   Fine 
Loam 

A 

Sandy 

r 
No. 

% 

Average 

No. 

% 

Average 

% 

% 

Average 

% 

No. 

% 

Average 

1-A 

49.70 

3-A 

38.10 

10-A 

10.30 

14-A 

25.80 

48.90 

49.30 

37.80 

37.95 

10.10 

10.20 

25.20 

25.50 

2-A 

37.40 

4-A 

23.41 

11-A 

15.52 

15-A 

11.50 

36.80 

37.10 

22.35 

22.88 

15.54 

15.53 

11.20 

11.35 

5-A 

46.55 

■   7-A 

23.90 

12-A 

13,72 

16-A 

15.60 

48.10 

47.32 

23.90 

23.90 

13.62 

13.67 

15.60 

15.60 

6-A 

58.80 

Average 

28.94 

13-A 

14.50 

19-A 

13.30 

56.80 

57.80 

14.60 

14.55 

14.30 

13.80 

Average 

i  47.88 

17-A 

8.90 

20- A 

18.41 

8.98 

8.94 

18.38 

18.39 

18-A 
2 1-A 
26-A 

7.92 
7.87 
7.16 
7.09 
11.30 
11.81 

7.89 

7.12 

11.55 

22-A 
2  3-A 
24-A 

12.73 
12.22 
11.08 
10.90 
16.30 
16.17 

12.47 
10.99 
16.23 

Average 

!  11.18 

25-A 

11.17 

12.72 

11.94 

Average 

15.14 

Note. — Determinations  made  by  the  Division  of  Soil  Technology. 


Table  11 — Hygroscopic  Coefficient 


Diablo   Clay 

A 

Adobe 

Altamont  Clav 

A 

Loam 

San  Joaquin 
Loam 

A 

Sandy 

Hanford    Fine 
Loam 

A 

Sandy 

No. 

% 

Average 
% 

No. 

Average 

%             % 

No. 

% 

Average 

% 

No. 

% 

Average 

% 

1-A 

15.88 

3-A 

17.48 

14-A 

5.35 

10-A 

2.46 

15.08 

15.48 

18.45 

17.93 

4.70 

5.03 

2.51 

2.49 

2-A 

9.90 

4-A 

9,60 

15-A 

1.31 

11-A 

3.44 

9.48 

9.69 

7.00 

8.30 

1.39 

1.35 

3.45 

3.44 

5-A 

14.18 

7-A 

7.92 

16-A 

3.90 

12-A 

3.58 

13.90 

14.04 

5.92 

6.92 

3.60 

3.75 

3.45 

3.52 

6-A 

15.20 

Average 

11.05 

19-A 

1.66 

13-A 

2.50 

15.70 

15.45 

1.80 

1.73 

2.60 

2.55 

Average 

s  13.66 

20- A 

2.90 

17-A 

1.84 

3.02 

2.96 

1.62 

1.73 

22-A 

2.48 
2.89 

2.69 

18-A 

2.10 
2.00 

2.05 

23-A 

2.38 
2.53 

2.46 

21-A 

1.98 
1.92 

1.95 

24-A 

2.39 

26-A 

3.57 

24-A 

2.39 

3.52 

3.55 

2.37 

2.38 

Average 

2.66 

25-A 

1.78 
1.84 

1.81 

Note. — Determinations  made  by  the  Division  of  Soil  Technology. 


394  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


15 


10 


Moisture 
Equiv. 


Hygro. 
Coef. 


10 


11 


12 


13 


18 


21 


2G  Soils 


20 


ir> 


10 


X 

\ 

^ 

\ 

-"" 

Moisture 
Equiv. 


10 


20 


22 


23 


24 


Hygro. 
Coef. 

23  Soils 


Fig.  10.  Graph  showing  the  results  of  the  determination  of  the  moisture 
equivalent  and  of  the  hygroscopic  coefficient  on  the  eight  samples  of  San 
Joaquin  sandy  loam  and  the  nine  samples  of   Ilanford  fine  sandy  loam. 


Hygroscopic  Coefficient. — The  determination  of  this  coefficient, 
also  by  the  Division  of  Soil  Technology,  shows  no  very  distinct  values 
for  the  several  types  under  consideration  (table  11,  figs.  9,10).  The 
Diablo  clay  adobe  samples  vary  from  9.6%  to  15.4%,  with  the  average 
of  13.69?  •  The  Altamont  clay  loam  samples  vary  from  6.9%  to 
17.9%,  averaging  11%.     The  San  Joaquin  sandy  loam  varies  from 


1919] 


Pendleton:   A  Study  of  Soil  Types 


39; 


1.7%  to  3.5%,  with  the  average  of  2.66%,  while  the  Hanford  fine 
sandy  loam  varies  from  1.3%  to  5%,  with  the  average  of  2.68%. 
There  is  no  question  that  here  the  range  of  values  within  every  type 
is  greater  than  that  from  type  to  type.  Even  excluding  those  sam- 
ples shown  by  the  mechanical  analysis  to  be  not  true  to  name  there 
is  a  wide  range  within  each  type — a  range  too  wide  to  allow  one 
to  answer  the  question  of  this  paper  in  the  affirmative. 

% 


V.6 
0.2 
0.1 
00 

P205 

N 


6  Soils 


Fig.  11.     Graph  showing  the  percentages  of  nitrogen  and  of  phosphorus  in 
the  four  samples  of  Diablo  clay  adobe. 


The  Chemical  Data 

Total  Nitrogen 

Diablo  clay  adobe. — There  is  more  variation  in  nitrogen  content 
between  the  different  representatives  of  the  type  than  one  would 
expect  from  a  visual  examination  of  the  soils  (table  12  and  fig.  11). 
No.  2  would  be  expected  to  contain  less  nitrogen  than  no.  5  because  of 
the  lighter  color,  but  such  is  not  the  case.  In  the  A  horizon,  no.  5 
shows  the  lowest  notal  nitrogen  content  with  0.084%,  no.  2  is  higher 
with  0.092%,  no.  1  with  0.104%,  and  no.  6  is  the  highest  with  0.117%. 
The  decrease  in  the  nitrogen  content  with  the  increase  in  depth  is 
normal.  In  the  C  horizon,  no.  1  has  the  lowest  total  nitrogen  content 
with  0.057%,  and  no.  6  the  highest,  with  0.078  %. 

Altamont  clay  loam. — The  agreement  between  the  A  samples  is 
fairly  close  (table  13,  and  fig.  12).  No.  4  has  0.103%,  no.  7,  0.104%, 
and  no.  3  has  0.123%.  This  gives  an  average  for  the  surface  soil  of 
0.110%,  as  compared  with  0.099%  in  the  Diablo  clay  adobe.  It  is  to 
be  noted  that  the  nitrogen  content  of  the  subsoil  is  relatively  less 
than  that  in  the  Diablo  subsoils,  0.071%  and  0.056%  in  the  Altamont 
B  and  C  horizons,  respectively,  as  against  0.076%  and  0.065%  in  the 


396 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


B  and  C  horizons  of  the  Diablo.  The  average  amount  of  nitrogen  is 
higher  in  the  A  horizon  of  the  Altamont  than  in  the  Diablo,  contrary 
to  what  one  would  expect  from  the  color  of  the  soils,  since  the  Alta- 
mont is  typically  a  brown  soil  and  the  Diablo  a  dark  gray  to  black  soil. 
San  Joaquin  sandy  loam. — The  nitrogen  content  of  these  soils  is 
uniformly  low  (table  14  and  fig.  13),  from  0.03%  to  0.05%,  and  is  but  a 
third  to  a  half  of  what  Hilgard  believed  adequate  for  crop  production. 


0.6 
0.2 
0.1 
00 

P205 


7  Soils 


Fig.  12.     Graph  showing  the  percentages  of  nitrogen  and  of  phosphorus  in 
the  three  samples  of  Altamont  clay  loam. 


^  P2Q5 


0.0 


26  Soils 

Fig.  13.     Graph  showing  the  percentages  of  nitrogen  and  of  phosphorus  in 
the  eight  samples  of  San  Joaquin  sandy  loam. 


The  nitrogen  content  is  seen  to  vary  more  or  less  directly  with  the 
amount  of  the  finer  sediments  present  in  the  soil — nos.  11  and  12 
being  heavy  members  of  the  type,  with  0.05%  and  0.047%  respec- 
tively, and  nos.  17  and  18  light  members  of  the  type  with  0.029%  and 
0.027%  respectively.  It  may  be  noted  that  the  nitrogen  content  of 
the  various  horizons  are  not  as  far  apart  as  in  the  other  types.  The 
averages  for  the  three  horizons  are:  A — 0.037%,  B — 0.027%,  and 
C — 0.026%.  It  must  be  borne  in  mind  that  the  San  Joaquin  sandy 
Loam  horizons  are  not  full  12-inch  samples,  and  that  the  total  depth 
of  the  sampling  is  less. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


397 


Han  ford  fine  sandy  loam. — Here  again  in  the  A  horizon  the  nitro- 
gen content  is  fairly  uniform  (table  15,  and  fig.  14),  with  from  0.045% 
to  0.072%,  if  the  extra  typical  no.  14,  with  0.119%,  be  left  out  of 
consideration.     One  would  suppose  these  soils  to  be  higher  in  their 


or 
0.9 


0.8 


0.7 


0.6 


0.5 


0.4 


0.3 


0.2 


0.1 


0.0 


x 

/ 

\ 

—  — -~ 

—  -^.^ 



P205 


16 


19 


20 


22 


23 


24 


25  Soils 


Fig.  14.     Graph  showing  the  percentages  of  nitrogen  and  of  phosphorus  in 
the  nine  samples  of  Hanford  fine  sandy  loam. 


nitrogen  content,  as  compared  with  the  San  Joaquin  series,  than  the 
results  show.  The  B  and  C  horizons  of  the  Hanford  samples  contain 
0.038%  and  0.028%  nitrogen,  respectively,  showing  that  with  the 
increase  of  deriih  there  is  a  more  rapid  decrease  of  nitrogen  than  in 
the  San  Joaquin  samples,  with  the  nitrogen  content  of  the  C  horizon 
of  the  Hanford  only  0.002%  above  that  of  the  C  horizon  of  the  San 


398 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Joaquin.  The  greenhouse  pot  cultures  showed  the  effect  of  the  much 
higher  nitrogen  content  in  no.  14  in  giving  better  color  and  growth 
to  the  plants  and  especially  to  the  grains.  The  increase  of  the  nitrogen 
in  the  surface  of  no.  23,  as  compared  with  the  B  and  C  horizons, 
might  be  ascribed  to  the  fertilizers  applied  to  the  orange  grove  where 
this  sample  was  collected;  yet  no.  24  is  a  truck  soil  which  has  been 
fertilized  to  a  considerable  extent  with  barnyard  manure.  The  nitro- 
gen content  of  this  type,  as  judged  by  the  previous  standards,  is 
quite  inadequate. 

Compare  the  nitrogen  content  of  the  A  horizons  of  the  four  types : 
The  Diablo  has  an  average  of  0.099%,  with  a  range  or  from  0.084% 
to  0.117%  ;  the  Altamont  has  an  average  of  0.110%,  with  a  range  of 
from  0.103%  to  0.123%; ;  the  San  Joaquin  has  an  average  of  0.037%?, 
with  a  range  of  from  0.027%  to  0.050% ;  and  the  Hanford  has  an 
average  of  0.062%,  with  a  range  of  from  0.045%  to  0.119%.  Thus 
the  total  nitrogen  content  of  the  several  types  is  reasonably  constant 
within  the  type  and  rather  distinct  for  the  types. 


Table  12- 

-Total  Nitrogen 

Diablo  Clay  Adobe 

Horizon 

A 

le 

A 

% 

Average 

% 

B            Average 

%                  % 

C 

% 

Average 

% 

0.109 

0.105 

0.076         0.069 

0.056 

0.057 

0.101 

0.063 

0.059 

0.100 

0.072 

0.062 

0.084 

0.092 

0.064         0.068 

0.058 

0.060 

0.085 

0.065 

No  sample 

0.084 

0.084 

0.065         0.065 

0.114 

0.097 

0.075 

0.122 

0.118 

0.107         0.102 

0.083 

0.079 

iver 

age 

0.100 

0.076 

0.065 

Sample 
3 


A 

% 

0.123 
0.124 
0.103 
0.103 
0.106 
0.104 


Table  13 — Total  Nitrogen 
Altamont  Clay  Loam 

Horizon 


Average 


Average 

% 


0.123 

0.103 

0.105 
0.110 


B 

% 

0.089 
0.087 
0.054 
0.053 
0.070 
0.077 


Average 

% 


0.088 

0.053 

0.073 
0.071 


C 

% 

0.069 
0.067 
0.041 
0.041 
0.061 
0.059 


Average 

% 


0.068 
0.041 
0.041 

0.060 
0.056 


1919] 


Pendleton:   A  Study  of  Soil  Types 


399 


Table  14 — Total  Nitrogen 
San  Joaquin  Sandy  Loam 
Horizon 


Sample 

A 

% 

Average 

% 

B 

% 

Average 

% 

C 

% 

Average 

% 

10 

0.037 

0.026 

0.022 

0.038 

0.037 

0.029 

0.027 

0.020 

0.021 

11 

0.051 

0.042 

0.038 

0.051 

0.051 

0.046 

0.044 

0.040 

0.039 

12 

0.049 

0.032 

0.042 

0.045 

0.047 

0.034 

0.033 

0.040 

0.041 

13 

0.040 

0.038 

0.033 

0.040 

0.040 

0.043 

0.040 

0.033 

0.033 

17 

0.028 

0.019 

No  sample 

0.030 

0.029 

0.018 

0.018 

18 

0.028 

0.016 

0.018 

0.028 

0.017 

0.016 

0.021 

0.019 

21 

0.029 

0.012 

0.014 

0.030 

0.029 

0.012 

0.012 

0.014 

0.014 

26 

0.041 

0.026 

0.016 

0.041 

0.041 

0.027 

0.026 

0.017 

0.016 

Average 

0.038 

0.027 

0.026 

Sample 
14 

15 

16 

19 

20 

22 

23 

24 
25 


Average 


Table  15- 

—Total 

Nitrogen 

Hanford 

Fine  Sandy  Loam 
Horizon 

A 

A 

% 

Average 

% 

B 

% 

Average 

% 

C 

% 

Average 

% 

0.113 

0.084 

0.060 

0.126 

0.119 

0.081 

0.082 

0.057 

0.058 

0.052 

0.039 

0.028 

0.055 

0.053 

0.043 

0.041 

0.027 

0.028 

0.058 

0.030 

0.020 

0.054 

0.056 

0.030 

0.023 

0.021 

0.046 

0.025 

0.024 

0.023 

0.044 

0.045 

0.025 

0.025 

0.023 

0.023 

0.062 

0.032 

0.024 

0.058 

0.060 

0.034 

0.033 

0.022 

0.023 

0.057 

0.033 

0.025 

0.061 

0.059 

0.036 

0.034 

0.023 

0.024 

0.075 

0.028 

0.020 

0.071 

0.073 

0.030 

0.029 

0.016 

0.018 

0.050 

0.032 

0.034 

0.028 

0.028 

0.045 

0.031 

0.022 

0.047 

0.046 

0.032 

0.031 

0.024 

0.023 

0.062 

0.038 

0.027 

400 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Humus 

Diablo  clay  adobe. — The  variations  in  the  humus  content  of  the  A 
samples  (table  16,  and  fig.  15)  are  moderate,  1.1%  to  1.4%,  while  the 
B  and  C  horizons  do  not  agree  so  closely  with  each  other  or  with  the 


Loss  on 
Ignition 


/ 
/ 

/ 

/ 

/ 

/ 
/ 

/ 
/ 
/ 
/ 

/ 

/ 

/ 

_. 

/ 
/ 

—•  — ::-~" 

N>.. 

<■ -*K, 

/ 
/. 

X. 

X 
X 
\ 

. — 

2 .-__ 


MgO 


K20 


Humus 


■  CaO 


Soils 


Fig.  15.  Graph  showing  the  loss  on  ignition,  the  amount  of  humus,  and 
the  percentages  of  calcium,  magnesium,  and  potassium  in  the  four  samples 
of  Diablo  clay  adobe. 


surface  foot.  The  average  content  of  humus  in  the  A  samples  is 
1.26%,  in  the  B  samples  0.95%,  and  in  the  C  samples  0.75%.  It  is 
worthy  of  note  that  soil  no.  2,  with  the  lightest  color  of  the  four,  and 
what  might  be  supposed  to  be  a  lower  humus  content,  has  next  to  the 
highest  amount. 


1919] 


Pendleton:  A  Study  of  Soil  Types 


401 


Altamont  clay  loam. — Here  the  variations  in  the  humus  content 
(table  17,  and  fig.  16)  are  small  in  the  A  horizon,  1.1%  to  1.3%.  The 
average  is  1.24%.  The  B  and  C  samples  show  a  good  parallelism 
among  themselves,  but  not  so  good  when  compared  with  the  surface. 
The  average  of  the  B  horizon  is  0.84%,  and  of  the  C  horizon  0.57%. 


\ 


\ 


V 


y 


/ 


/ 


/ 


/ 


^L- 


/ 


Loss  on 
Ignition 


K20 

Humus 
CaO 

MgO 


3  4  7  Soils 

Fig.  16.  Graph  showing  the  loss  on  ignition,  the  amount  of  humus,  and  the 
percentages  of  calcium,  magnesium,  and  potassium  in  the  three  samples  of  Alta- 
mont  clay  loam. 


San  Joaquin  sandy  loam. — This  type  contains  a  considerable  quan- 
tity of  humus  (table  18,  and  fig.  17)  when  one  takes  into  considera- 
tion the  popular  criteria  for  the  presence  of  humus,  for  the  red  to 
reddish  brown  San  Joaquin  soils  are  very  different  from  the  brown 
Altamont  or  the  black  Diablo  soils.     The  samples  of  this  type  gave 


40: 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.3 


light  colored  or  nearly  colorless  humus  solutions.  But  when  the  ali- 
quots  were  ignited,  after  evaporation,  there  was  a  very  noticeable 
blackening  and  charring  of  the  residue,  together  with  a  considerable 


/ 

\ 

/ 

\ 

/ 

\ 

/ 

/ 

\ 

/ 

\ 

/ 

/    J 
/ 

i\\ 

/ 

/ 

/ 

"v\ 

/ 
/ 

/ 

/ 

v 

/ 

\  / 

/ 

/ 

\\ 

Y 

/ 

/ 

s 

/ 

/ 

V 
A 

/ \ 

/   \ 

/ 

/  x 

V-— .. 

/ 
/ 

/ 

\ 

^^**». 

\      / 

\ 

\/ 

\ 

\ 

/  \ 

\ 

/ 

t- : 

"  ** 

.... 

^ 

\ 

""■:./ 

*«« 

... *"^»l 

****■••—.. 

\, 

y 

••<Sv^ 

->< 

y 

"-N... 

^ 

Loss  on 
Ignition 


K2O 


Humus 


MgO 
CaO 


10 


12 


L3 


17 


IS 


21  26  Soils 

Fig.  17.  Graph  showing  the  loss  on  ignition,  the  amount  of  humus,  and 
the  percentages  of  calcium,  magnesium,  and  potassium  in  the  nine  samples  of 
San  Joaquin  sandy  loam. 


loss  in  weight.  This  phenomenon,  in  the  light  of  the  work  of  Gortner,27 
shows  that  these  soils  have  a  "humus"  content  above  that  which  they 
might  be  supposed  to  have,  because  of  the  almost  complete  absence  of 


27  soil  Science,  vol.  2  (1916),  pp.  395-442. 


1919]  Pendleton:   A  Study  of  Soil  Types  403 

the  "black  pigment."  Soil  no.  26,  probably  the  only  virgin  soil  in 
the  series,  shows  a  particularly  high  content  of  humus  for  such  a  soil, 
though  from  the  color  of  the  soil  one  would  suspect  but  very  little 
humus.  The  agreement  between  the  three  horizons  of  the  San  Joaquin 
sandy  loam  samples  is  close.  The  average  content  of  humus  was 
0.68%  in  the  A,  0.51%  in  the  B,  and  0.38%  in  the  C  horizon. 

Han  ford  fine  sandy  loam. — The  variations  in  humus  content  in  this 
type  are  greater  than  in  any  of  the  others  (table  19,  and  fig.  18).  This 
is  possibly  because  of  two  factors :  the  open  texture  of  the  soil,  hence 
the  rapid  loss  of  organic  matter  by  oxidation  processes ;  and  secondly, 
the  high  agricultural  value  of  this  soil,  which  has  led  to  a  greater  appli- 
cation of  fertilizers  than  has  been  the  case  with  the  other  soils.  The 
actual  variations  in  the  humus  content  are  large,  0.7%  to  2.1%  with 
the  average  of  1.15%  for  horizon  A,  from  0.5%  to  1.8%  with  the  aver- 
age of  0.81%  for  B,  and  from  0.44%  to  1.07%  with  the  average  of 
0.59%  for  C.  The  extra-typical  sample  no.  14  is  above  any  of  the 
others  in  the  total  humus  content.  The  variations  in  the  subsoil 
humus  content  are  more  or  less  parallel  to  those  of  the  surface  soil. 

The  following  averages  of  the  humus  content  of  horizon  A,  Diablo 
1.26%,  Altamont  1.24%,  San  Joaquin  0.68%,  Hanford  1.15%,  show 
that  there  is  not  much  difference  between  the  soils,  except  for  the  San 
Joaquin  sandy  loam,  which  has  an  average  of  half  the  others.  Within 
the  type  the  soils  may  be  nearly  alike,  as  in  the  San  Joaquin  and  Alta- 
mont, or  may  be  variable  to  a  large  degree,  as  in  the  Hanford.  The 
variations  in  the  humus  content  of  the  soils  are  small,  considering  the 
diverse  nature  of  the  soils,  and  the  usual  methods  for  judging  the 
quantity  of  humus. 

Table  16 — Humus  (and  Humus  Ash) 
Diablo  Clay  Adobe 


Humus 
Horizons 

A 

Humus  ash 
Horizons 

A 

Sample 

A 

% 

Average 

% 

B 

Average      C 

%           % 

Average 

% 

A    Average 

%           % 

B 

% 

Average 

% 

C 

% 

Aver- 
age 

% 

1 

1.08 

0.51 

0.18 

0.55 

0.75 

0.45 

1.08 

1.08 

0.51 

0.51 

0.24 

0.21 

0.56 

0.56 

0.73 

0.74 

0.46 

0.46 

2 

1.40 

1.16 

1.09 

1.01 

0.96 

1.09 

1.38 

1.39 

1.15 

1.15 

1.02 

1.06 

1.03 

1.02 

0.96 

0.96 

0.96 

1.03 

5 

1.17 

0.87 

1.08 

1.19 

1.12 

1.15 

0.91 

0.89 

1.10 

1.09 

1.14 

1.17 

6 

1.48 

1.26 

0.95 

0.98 

0.88 

0.78 

Werag 

1.37 

3 

1.43 
1.26 

1.26 

1.26 
0.95 

0.99 

0.97 
0.72 

0.95 

0.96 
0.91 

0.91 

0.90 
0.95 

0.85 

0.81 
0.77 

404 

% 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Humus 


14  15  H>  19  20  22  23  24  25  Soila 

Pig.  18.  Graph  showing  the  loss  on  ignition,  the  amount  of  humus,  and 
the  percentages  of  calcium,  magnesium,  and  potassium  in  the  nine  samples  of 
Hanford  fine  sandy  loam. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


405 


Table  17 — Humus  (and  Humus  Ash) 


Altamont  Clay  Loam 


Humus 
Horizons 


A     Average  B  Average  C     Average 

Sample       %            %  %  %  %  % 

3  1.06  0.89  0.59 

1.13  1.09  0.84  0.86  0.58  0.59 

4  1.30  0.69  0.59 

1.33  1.31  0.71  0.70  0.28  0.43 

7         1.32  0.95  0.68 

1.31  1.32  0.96  0.96  0.68     0.68 

Average  1.24  0.84           .  0.57 


Humus  ash 
Horizons 


Aver- 

A    Average  B     Average     C  age 

%  %  %  %  %  % 

1.29  1.08  0.95 

1.23     1.26  1.28     1.18     0.95  0.95 

0.80  0.98  0.91 

0.85     0.83  0.98     0.98     1.03  0.97 

0.72  0.87  1.09 

0.75     0.74  0.88     0.88     1.08  1.08 

0.94  1.01  1.00 


Table  18 — Humus  (and  Humus  Ash) 
San  Joaquin  Sandy  Loam 


Humus 
Horizons 

A 

Humus   ash 
Horizons 

A 

Sample 

A     Average 

%           % 

B     Average 

%          % 

C      Average 

%          % 

A    Average 

%           % 

B      Average 

%           % 

C 

% 

Aver- 
age 

% 

10 

0.66 

0.66 

0.53 

0.53 

0.27 

0.27 

1.31 

1.31 

1.33 

1.33 

0.67 

0.67 

11 

0.75 

0.41 

0.37 

0.51 

0.66 

0.58 

0.71 

0.73 

0.41 

0.37 

0.69 

0.60 

0.66 

0.58 

12 

0.62 

0.49 

0.32 

0.88 

1.50 

0.80 

0.65 

0.64 

0.49 

0.32 

0.95 

0.91 

1.50 

0.80 

13 

0.75 

0.50 

0.35 

1.38 

0.90 

1.02 

0.78 

0.77 

0.50 

0.35 

1.36 

1.37 

0.90 

1.02 

17 

0.51 
0.51 

0.51 

0.38 

0.38 

0.53 
0.57 

0.55 

1.23 

1.23 

18 

0.56 

0.60 

0.42 

0.61 

0.76 

1.79 

0.60 

0.58 

0.58 

0.59 

0.42 

0.56 

0.59 

0.75 

0.76 

1.79 

21 

0.52 

0.19 

0.18 

0.53 

0.37 

0.37 

0.52 

0.52 

0.21 

0.40 

0.21 

0.19 

0.54 

0.53 

0.37 

0.37 

0.48 

0.42 

26 

1.04 

0.79 

0.68 

0.89 

3.57 

5.28 

1.01 

1.02 

0.79 

0.79 

0.82 

0.75 

0.76 

0.83 

3.63 

3.60 

5.46 

5.35 

Average 

0.66 

0.51 

0.38 

0.83 

1.24 

1.51 

Excluding  no. 

26 

0.95 

0.87 

Loss  on  Ignition 

The  loss  on  ignition  of  the  A  horizon  varies  directly  with  the  tex- 
ture of  the  soil,  the  heavier  soils  losing  more  on  heating.  Obviously 
the  water  of  combination  of  the  clay  is  a  large  factor  in  this  loss.  In 
the  San  Joaquin  sandy  loam  the  loss  on  ignition  was  determined  in 
the  three  horizons.  In  the  other  three  types  the  A  horizon  was  the 
only  one  examined  (tables  20,  21,  and  figs.  15-18). 


406 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table 

19 — Humus 

(and 

Humu 

s  Ash 

0 

. 

Hanford  Fin 

,e  Sandy  Loam 

Humus 
Horizons 

Humus  ash 
Horizons 

Sample 

A 

% 

Average      B 

%           % 

Average      C 

%           % 

Average 

A    Average 

%           % 

B      Average 

%           % 

C 

% 

Aver- 
age 

% 

14 

2.11 

1.81 

1.10 

1.14 

1.24 

1.01 

2.09 

2.10 

1.78 

1.79 

1.05 

1.07 

1.17 

1.16 

1.27 

1.26 

1.09 

1.05 

15 

1.79 

0.88 

1.04 

1.88 

0.94 

0.92 

1.77 

1.78 

0.93 

0.90 

0.67 

0.86 

1.85 

1.86 

0.89 

0.92 

0.91 

0.92 

16 

1.20 

0.73 

0.41 

0.91 

0.93 

0.90 

1.20 

1.20 

0.73 

0.73 

0.46 

0.44 

0.91 

0.91 

1.47 

0.93 

0.90 

0.90 

19 

0.73 

0.51 

0.45 

0.48 

0.57 

0.78 

0.74 

0.73 

0.50 

0.51 

0.55 

0.50 

0.47 

0.48 

0.58 

0.58 

0.76 

0.77 

20 

1.08 

0.86 

0.59 

0.52 

0.90 

0.79 

1.06 

1.07 

0.89 

0.88 

0.50 

0.55 

0.56 

0.54 

0.90 

0.90 

0.78 

0.78 

22 

0.96 

0.73 

0.58 

0.59 

0.60 

0.58 

0.96 

0.96 

0.71 

0.72 

0.56 

0.57 

0.59 

0.59 

0.60 

0.60 

0.63 

0.61 

23 

1.04 

0.59 

0.38 

0.58 

0.45 

0.39 

1.07 

1.05 

0.62 

0.61 

0.38 

0.38 

0.57 

0.58 

0.41 

0.43 

0.37 

0.38 

24 

0.73 

0.55 

0.56 

0.58 

0.69 

0.82 

0.73 

0.73 

0.61 

0.58 

0.51 

0.54 

0.56 

0.57 

0.69 

0.69 

0.80 

0.81 

25 

0.71 

0.58 

0.45 

0.57 

0.67 

0.74 

0.69 

0.70 

0.56 

0.57 

0.42 

0.44 

0.61 

0.59 

0.71 

0.69 

0.78 

0.76 

Average 

1.15 

0.82 

0.59 

0.81 

0.78 

0.78 

Diablo  clay  adobe. — The  variation  in  these  samples  was  from 
5.6%  to  8.6%,  with  the  average  of  6.8%.  The  Altamont  clay  loam 
has  a  variation  of  from  5%  to  8.7%,  averaging  6.7%.  The  San  Joa- 
quin sandy  loam  has  a  range  of  variation  between  1.6%  and  4.2%, 
with  an  average  of  2.6%.  The  loss  on  ignition  of  the  lower  horizons 
increases  over  that  of  the  surface,  because  of  the  increase  in  texture. 
The  B  horizon  shows  an  average  loss  of  3.9%  and  the  C  horizon  of 
4.67%.  The  Hanford  fine  sandy  loam  range  of  variation  in  the  loss 
on  ignition  is,  excluding  no.  14,  from  2.2%  to  3.9%,  with  an  average 
of  3.4%.  Thus  the  curve  for  this  type  is  quite  uniform,  except  for 
no.  14,  which  shows  a  loss  of  6.9%. 

It  is  seen  that  the  averages  in  the  loss  on  ignition  of  the  A  horizons 
of  the  Diablo  and  Altamont  soils  are  close,  and  high,  6.8%  and  6.7% 
respectively.  The  averages  of  the  San  Joaquin  and  Hanford  sam- 
ples, 2.6%  and  3.4%  respectively,  are  low  and  not  widely  separated. 
Since  the  values  for  the  types  overlap  considerably,  and  the  averages 
are  not  distinct,  except  between  the  light  and  heavy  groups,  there  is 
no  significant  distinction  between  the  four  types  by  this  determination. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


407 


Table  20 — Loss  on  Ignition 
(Surface  horizon  only) 


Diab 

lo  Clay  Adobe 

A * 

% 

Altamont  Clay 

% 

Loam 

% 

Hanford  Fine 
Loam 

A 

Sandy 

^ 

% 

% 

1-A 

6.62 

3-A 

8.74 

14-A 

6.90 

6.66 

6.64 

8.82 

8.78 

6.95 

6.92 

2-A 

6.57 

4-A 

5.05 

15-A 

2.27 

6.64 

6.60 

5.05 

5.05 

2.30 

2.28 

5-A 

5.61 

7-A 

6.58 

16-A 

3.26 

5.61 

6.46 

6.52 

3.24 

3.25 

6-A 

8.67 
8.71 

8.69 

A 

verage 

6.78 

19- A 

3.10 
3.13 

3.11 

Average 

6.88 

20-A 

3.90 

3.94 

3.92 

2  2-A 

3.06 
3.07 

3.06 

23-A 

3.48 
3.45 

3.46 

24-A 

2.60 
2.60 

2.60 

2  5-A 

2.68 

2.72 

2.70 

Average 

3.48 

Table  21 — Loss  on  Ignition 
San  Joaquin  Sandy  Loam 


Sample 

A 

% 

Average 

% 

10 

2.13 

2.17 

2.15 

11 

3.23 

3.20 

3.21 

12 

5.37 

3.22 

4.29 

13 

2.94 

2.96 

2.95 

17 

1.85 

1.88 

1.86 

18 

1.82 

1.83 

1.82 

21 

1.68 

1.69 

1.68 

26 

3.30 

3.30 

Avera 

ge 

2.66 

Ho 

rizon 

A 

B 

% 

Average 

% 

2.32 

2.27 

2.29 

6.33 

6.16 

6.24 

2.97 

3.18 

3.07 

6.58 

6.75 

6.66 

2.54 

2.61 

2.57 

2.18 

2.18 

2.18 

1.60 

1.56 

1.58 

6.97 

6.95 

6.96 

3.94 

c 

% 

3.10 
3.08 
6.57 
6.67 


Average 


3.09 


6.62 


5.54 

5.54 

3.97 

6.07 

5.02 

NO! 

sample 

2.90 

2.89 

2.89 

3.31 

3.33 

3.32 

6.18 

6.18 

4.67 


408  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

Calcium 

The  Diablo,  Altamont,  and  Hanford  soils  were  analyzed  for  their 
calcium  in  the  A  horizon  only,  while  the  A,  B,  and  C  horizons  of  the 
San  Joaquin  sandy  loam  were  analyzed  (tables  22,  23,  and  figs.  15-18). 

Diablo  clay  adobe. — There  is  much  divergence  in  the  amounts  of 
CaO  in  this  type,  varying  from  0.36%  to  2.05%,  with  the  average 
of  1.23%. 

Altamont  clay  loam. — In  this  type  there  is  a  little  greater  varia- 
tion than  in  the  Diablo  samples,  with  a  range  of  from  0.78%  to  5.64%, 
averaging  2.44%  CaO.  In  both  this  soil  and  in  the  Diablo  the  wide 
variation  in  the  lime  content  is  undoubtedly  due  to  the  nature  of  the 
parent  rock,  since  the  soils  are  residual: 

San  Joaquin  sandy  loam. — In  the  CaO  content  there  is  no  uni- 
formity among  the  samples.  The  A  samples  of  this  type  contain  from 
0.47%  to  2.98%,  with  an  average  of  1.65%.  It  would  seem  that  the 
materials  from  which  the  soils  were  derived  were  of  varying  composi- 
tion. For  from  the  present  climatic  conditions  soil  no.  25  is  the  one 
subject  to  the  least  leaching,  and  yet  has  the  least  CaO  content.  The 
B  and  C  percentages  follow  the  surface  very  closely — sufficiently  so 
to  necessitate  no  particular  explanation.  The  range  of  variation  in 
the  B  horizon  is  from  0.11%  to  2.42%,  and  the  average  is  1.42%. 
The  C  samples  vary  from  0.17%  to  2.81%,  with  the  average  of  1.52%. 

Hanford  fine  sandy  loam. — The  A  samples  of  this  type  contain 
from  2.56%  CaO  to  4.69%,  with  3.33%  as  the  average.  The  varia- 
tions are  not  so  marked  among  the  series  of  this  type  as  in  the  cases 
of  the  other  three  soils.  The  absolute  range  is  nearly  as  great,  but 
the  relative  variation  is  less. 

Even  though  there  are  differences  between  the  average  CaO  con- 
tent in  the  several  types,  the  wide  variation  in  the  amount  found  in 
the  several  samples  of  a  given  type,  and  the  overlapping  of  these 
amounts  from  the  different  types  entirely  preclude  any  statement 
that  as  regards  the  calcium  content  the  soils  of  any  one  type  are 
closely  similar  to  one  another,  or  that  one  type  has  a  higher  or  lower 
lime  content  than  another. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


409 


Table  22 — Calcium  as  CaO 
(Surface  horizons  only) 


Bh 

iblo  Clay  Adobe 

A 
% 

Altamont  Clay 

A 

Loam 

Hanford  Fine 
Loam 

Sandy 

r~ 

% 

% 

% 

% 

1-A 

1.86 

3-A 

5.64 

14-A          2.91 

1.80 

1.83 

5.64 

2.99 

2.95 

2-A 

2.12 

4-A 

0.92 

15-A          2.98 

1.98 

2.05 

0.88 

0.90 

3.22 

3.10 

5-A 

0.56 

7-A 

0.89 

16-A         2.48 

0.17 

0.36 

0.67 

0.78 

2.65 

2.56 

6-A 

0.67 

0.67 

A 

verage 

2.44 

19-A         3.28 
3.17 

3.22 

Average 

1.23 

20-A         2.69 

2.73 

2.71 

22-A  >       3.80 

3.92 

3.86 

23-A          2.88 

3.00 

2.94 

24-A          3.88 

4.00 

3.94 

25- A          4.58 

4.80 

4.69 

Average 

3.33 

Table  23 — Calcium  as  CaO 
San  Joaquin  Sandy  Loam 
Horizon 


Sample 

r 
A 

% 

Average 

% 

B 

Average 

% 

C 

% 

Average 

% 

10 

0.67 

0.82 

1.11 

0.62 

0.64 

1.03 

0.92 

1.12 

1.11 

11 

1.94 

1.62 

1.65 

1.26 

1.60 

1.70 

1.66 

1.55 

1.60 

12 

3.12 

2.21 

2.61 

3.50 

3.31 

2.21 

3.01 

2.81 

13 

2.83 

2.38 

2.46 

3.13 

2.98 

2.46 

2.42 

2.79 

2.62 

17 

1.83 

1.92 

No 

sample 

2.08 

1.95 

2.08 

2.00 

18 

1.40 

1.00 

1.48 

1.34 

1.37 

1.45 

1.22 

1.42 

1.45 

21 

0.91 

0.89 

0.85 

0.84 

0.87 

0.83 

0.86 

0.89 

0.87 

26 

0.48 

0.13 

0.17 

Avei 

0.47 
age 

0.47 
1.65 

0.10 

0.11 
1.42 

0.17 

0.17 
1.52 

410 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Magnesium  as  MgO 

Diablo  clay  adobe. — This  type  shows  a  moderate  variability  in  the 
magnesium  content,  with  from  1.13%  MgO  to  3.26%,  averaging 
2.09%.  The  largest  quantity  is  three  times  that  of  the  smallest, 
(tables  24,  25,  figs.  15-18). 

Altamont  clay  loam. — Within  the  three  samples  of  this  type  the 
range  in  the  MgO  content  is  very  great,  from  0.07%  to  1.90%,  with 
the  average  of  1.05%.  The  largest  is  twenty-seven  times  that  of  the 
smallest. 

San  Joaquin  sandy  loam. — The  total  MgO  in  the  samples  of  the 
type  is  low,  considering  that  some  soils  reported  by  Hilgard  contain 
from  1%  to  3%  magnesia  by  the  acid  digestion.  The  variation  within 
the  A  horizon  is  from  0.34%  to  0.90%,  with  the  average  of  0.62%,  i.e., 
the  largest  is  three  times  the  smallest.  The  quantities  in  the  B  horizon 
are  somewhat  erratic  as  compared  with  those  of  the  surface,  yet  in 
both  the  B  and  C  horizons  the  results  approach  those  of  the  surface 
sufficiently  to  give  a  rough  parallelism.  The  greater  amount  of  clay 
and  fine  silts  with  the  increase  of  depth  gives,  as  one  would  expect, 
an  increase  of  magnesium.  The  average  MgO  content  in  the  B  horizon 
is  0.81%,  and  in  the  C  horizon  1.05%. 


Table  24 — Magnesium  as  MgO 
(Surface  horizon  only) 


Diablo  Clay  Adobe 

j 

ytamont  Clav 

A 

Loam 

Hani 

'ord  Fine  S 
Loam 

A 

andy 

r 

% 

% 

% 

% 

% 

% 

1-A 

1.64 

3- 

-A 

1.85 

14- A 

2.49 

2.20 

1.92 

1.95 

1.90 

2.49 

2.49 

2-A 

2.16 

4- 

-A 

1.21 

15-A 

0.93 

1.95 

2.05 

1.17 

1.19 

1.02 

0.97 

5-A 

1.23 

7- 

-A 

0.09 

16-A 

1.10 

1.03 

1.13 

0.05 

0.07 

0.99 

1.04 

6-A 

3.62 
2.90 

3.26 

A 

verage 

1.05 

19- A 

2.11 
1.99 

2.05 

Average 

2.09 

20- A 

1.77 
1.92 

1.84 

22-A 

2.44 
2.71 

2.57 

23-A 

1.94 
1.70 

1.82 

24-A 

2.14 
2.13 

2.13 

25-A 

2.31 
2.40 

2.35 

Average 

1.92 

1919] 


Pendleton:   A  Study  of  Soil  Types 


411 


Han  ford  fine  sandy  loam. — The  MgO  content  of  the  surface  soil 
varies  from  0.97%  to  2.57%,  averaging  1.92%.  The  relative  varia- 
tion within  this  type  is  about  that  of  the  Diablo  and  San  Joaquin 
types. 

Comparing  the  average  amounts  of  magnesium  oxide  in  the  sur- 
face horizon  of  the  several  types,  we  find  the  San  Joaquin  with  0.56%, 
the  Altamont  with  1.05%,  the  Hanford  with  1.93%,  and  the  Diablo 
with  2.09%.  The  averages  do  not  signify  much,  however,  because  of 
the  wide  ranges  within  the  types.  Therefore  as  regards  magnesium 
the  types  are  neither  distinct  nor  are  the  soils  within  the  type 
closely  similar. 

Table  25 — Magnesium  as  MgO 
San  Joaquin  Sandy  Loam 

Horizon 


Sample 

A 

% 

Average 

B 

% 

Average 

% 

C 

% 

Average 

% 

10- A 

0.31 

0.33 

0.53 

0.30 

0.30 

0.45 

0.39 

0.53 

0.53 

11-A 

0.79 

1.21 

1.48 

0.44 

0.61 

1.22 

1.21 

1.25 

1.36 

12- A 

0.83 

0.79 

1.57 

0.79 

0.81 

0.79 

1.62 

1.59 

13- A 

0.90 

1.70 

1.67 

0.80 

0.85 

1.63 

1.66 

1.82 

1.74 

17- A 

0.53 

0.51 

No  sample 

0.74 

0.63 

0.77 

0.64 

18-A 

0.50 

0.40 

0.64 

0.48 

0.49 

0.69 

0.54 

0.75 

0.69 

21-A 

0.29 

0.28 

0.52 

0.29 

0.31 

0.29 

0.56 

0.54 

26-A 

0.50 

0.52 

0.52 

0.52 

0.51 

0.44 

0.48 

0.53 

0.52 

Average 

0.56 

0.75 

1.00 

Phosphorus  as  P205 

Diablo  clay  adobe. — The  variations  in  the  P205  content  in  the 
samples  of  this  type  are  relatively  small,  from  0.092%  to  0.162%, 
with  0.108%  as  the  average  (tables  26,  27,  figs.  11-14). 

Altamont  clay  loam. — The  range  of  variation  in  the  amount  of 
P205  is  large,  from  0.031%  to  0.265%,  the  largest  quantity  being  eight 
times  the  smallest.    The  average  is  0.132%. 


412  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

San  Joaquin  sandy  loam. — The  variations  in  the  P205  content  of 
the  surface  soil  are  from  0.039%  to  0.11%,  with  the  average  0.068%. 
The  curve  is  fairly  regular.  The  subsoils  follow  the  surface  in  a  gen- 
eral way.  The  B  horizon  samples  vary  in  the  phosphoric  acid  con- 
tent between  0.028%  and  0.156%,  and  average  0.069%.  The  C  sam- 
ples vary  between  0.03%  and  0.109%,  and  average  0.067%.  The 
averages  of  the  three  horizons  are  seen  to  be  almost  identical.  No 
particular  significance  can  be  attached  to  the  minor  variations. 

Hanford  fine  sandy  loam. — The  P205  content  in  the  samples  of 
this  type  is  very  variable,  from  0.195%  to  0.819%,  with  the  average 
of  0.363%.  The  average  of  the  San  Joaquin  sandy  loam  samples  is 
0.069%,  of  the  Diablo  clay  adobe  0.108%,  of  the  Altamont  clay  loam 
0.132%,  and  of  the  Hanford  fine  sandy  loam  0.363%.  Except  between 
the  Diablo  and  Altamont  types  these  averages  would  show  considerable 
differences,  if  it  were  not  that  the  samples  frequently  show  such  wide 
departures  from  the  averages.  The  ranges  of  the  several  types  fre- 
quently overlap. 

Table  26 — Phosphorus  as  P205 

(Surface  horizon  only) 

Hanford  Fine  Sandy 
Diablo  Clay  Adobe  Altamont  Clay  Loam  Loam 

A .      „ A . A . 


%  %  %  %  %  % 

1-A         0.088  3-A         0.278  14-A         0.373 

0.096  0.092  0.252  0.265  0.292  0.333 

2-A         0.064  4-A  0.081  15-A         0.287 

0.078         0.071  0.117         0.099  0.260  0.273 

5-A         0.137  7-A         0.034  16-A  0.260 

0.082         0.109  0.028  0.031  0.277         0.268 

6-A         0.143  Average  0.132     19-A         0.303 

0.181  0.162  0.272         0.287 

Average  0.108  20-A         0.190 

0.200         0.195 
22-A         0.397 

0.401  0.399 

23-A         0.242 

0.270         0.256 
24- A         0.421 

0.454         0.437 
25-A         0.879 

0.759  0.819 

Average  0.363 


1919] 


Pendleton:   A  Study  of  Soil  Types 


413 


Table  27- 

-Phosphorus  as  P205 

San  Joaquin  Sandy  Loam 

Horizon 

A 

Sample 

A 

% 

Average 

% 

B 

% 

Average 

% 

C 

% 

Average 

% 

10 

0.118 

0.060 

0.047 

0.102 

0.110 

0.068 

0.064 

0.057 

0.052 

11 

0.049 

0.047 

0.049 

0.060 

0.054 

0.046 

0.046 

0.028 

0.028 

12 

0.057 

0.028 

0.064 

0.071 

0.064 

0.028 

0.095 

0.078 

13 

0.049 

0.037 

0.036 

0.064 

0.056 

0.038 

0.039 

0.024 

0.030 

17 

0.036 

0.041 

No  sample 

0.042 

0.039 

0.082 

0.061 

18 

0.043 

0.097 

0.086 

0.055 

0.049 

0.074 

0.085 

0.086 

21 

0.069 

0.088 

0.094 

0.068 

0.068 

0.066 

0.077 

0.062 

0.078 

26 

0.117 

0.130 

0.120 

0.092 

0.104 

0.182 

0.156 

0.098 

0.109 

Average 

0.068 

0.069 

0.067 

Potassium  as  K20 

Diablo  clay  adobe. — There  is  a  moderate  range  in  the  variation  in 
the  amount  of  K20  within  this  type,  the  lowest  amount  being  1.48% 
and  the  highest  2.06%,  the  four  samples  averaging  1.71%  (table  28, 
figs.  15-18). 

Altamont  clay  loam. — A  greater  variation,  from  1.09%  to  2.14%, 
of  K20,  occurs  in  the  three  samples  of  this  type.  The  average  is 
1.74%. 

San  Joaquin  sandy  loam. — This  type  shows  the  greatest  variation, 
from  0.98%  to  2.84%.  But  even  so,  the  the  largest  quantity  of  K20 
is  less  than  three  times  the  smallest.  1.88%  K20  is  the  average  of 
the  eight  samples.  Nos.  11  and  12  of  this  type  show  the  smallest 
amounts  of  K20  of  any  of  the  twenty-four  samples. 

Hanford  fine  sandy  loam. — The  variation  in  the  K20  content  of 
the  samples  of  this  type  is  not  great — from  1.73%  to  3.16%,  with 
the  average  of  2.33%.  This  is  the  highest  average,  as  the  Diablo  clay 
adobe  samples  show  1.71%,  the  Altamont  clay  loam  1.74%,  and  the 
San  Joaquin  sandy  loam  1.88%.  Because  of  the  considerable  range 
in  the  amounts  of  K20  for  the  several  samples  of  a  type,  and  because 
of  the  many  overlappings  of  the  values  for  one  type  over  another, 
the  averages  do  not  mean  much  and  do  not  show  the  soils  within  a 
type  to  be  closely  similar,  nor  do  they  show  the  types  distinct. 


414  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

Table  28 — Potassium  as  K20 

(J.  Lawrence  Smith  Method) 

Hanford  Fine  Sandy 


Dii 

iblo  Clay 

Adobe 

Altamont  Clay 

Loam 

San  Joaqu 

in  Sandy  Loam 

Loam 

No. 

% 

Average 

% 

Xo. 

% 

Average 

% 

No. 

% 

Average 

% 

r 

No. 

Average 

% 

1-A 

1.68 

3-A 

1.06 

14-A 

1.79 

10- A 

2.14 

1.67 

1.67 

1.13 

1.09 

1.67 

1.73 

2.12 

2.13 

2-A 

1.62 

4-A 

1.92 

15-A 

2.54 

11-A 

0.99 

1.69 

1.65 

2.36 

2.14 

2.62 

2.58 

0.98 

0.98 

5-A 

1.45 

7-A 

1.90 

16-A 

2.42 

12-A 

1.03 

1.51 

1.48 

2.10 

2.00 

2.46 

2.44 

1.02 

1.02 

6-A 

2.01 
2.12 

2.06 

A 

verage 

1.74 

I9-A 

2.10 
2.03 

2.06 

13-A 

1.50 

1.50 

Average 

1.71 

20- A 

2.00 

17-A 

2.40 

1.81 

1.90 

2.24 

2.32 

2  2-A 

2.68 
2.62 

2.65 

18-A 

2.07 

2.28 

2.17 

23-A 

3.10 
3.23 

3.16 

2 1-A 

2.81 

2.88 

2.84 

24-A 

2.29 
2.21 

2.25 

2  6-A 

2.04 
2.09 

2.06 

25-A 

2.18 

Average 

1.88 

2.21 

2.19 

Average 

2.33 

Bacteriological  Data 

The  bacteriological  work  was  not  entirely  satisfactory,  partly  be- 
cause the  conditions  in  one  of  the  incubators  were  not  all  that  might 
be  desired,  and  partly  because  of  the  refractory  physical  properties 
of  some  of  the  soils.  The  Diablo  and  Altamont  types,  in  all  three 
horizons,  were  very  heavy  and  hard  to  mix  and  keep  in  even  fair 
physical  condition.  The  San  Joaquin  soils  were  predominantly  of  a 
heavy  texture  in  the  B  and  C  horizons,  while  the  surface  horizon 
was  light  and  the  crumb  structure  was  entirely  lost  if  even  a  small 
excess  of  water  was  added  to  the  culture. 


AMMONIFI  CATION 

There  arc  very  marked  differences  between  the  various  types  in 
tli is  determination,  though  the  samples  in  a  given  type  vary  among 
themselves  to  a  large  extent. 

Diablo  clay  adobe. — The  highest  ammonia  production  was  about 
three  limes  the  lowest,  7.7  mg.  and  26  mg.  In  both  this  type  and 
the  following,  the  B  and  C  horizons  follow  the  surface  horizon  quite 


1919] 


Pendleton:   A  Study  of  Soil  Types 


415 


-a 

£   40 

O 

^  30 

n 

X 

z 
S  20 


\    \ 

— - ^— 

N 

°l  £  5.  6 

Soi  Is. 

Fig.  19-A. 

Fig.  19a.  Graph  showing  ammonification  in  the  four  samples  of  Diablo  clay 
adobe.  The  quantities  are  expressed  in  terms  of  nitrogen  produced  per  100 
grams  of  soil  with  2%  of  dried  blood. 


x 


71 


\Q 


15 


SO 


25 


\ 

^ 

A        

B^^^" 

JZ^~  """" 

~^c 

0 

A  Z.  O  6. 

Soils. 

Fiq.  13  -B 

Fig.  19b.  Graph  showing  nitrogen  fixation  in  the  three  horizons  of  the  four 
samples  of  Diablo  clay  adobe.  The  quantities  are  expressed  in  terms  of  milli- 
grams of  nitrogen  fixed  per  gram  of  mannite  in  50  grams  of  soil. 


416 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


closely  from  sample  to  sample  (table  28  and  fig.  19a).  This  may  be 
due  to  the  textures,  which  are  quite  similar  throughout  the  soil  column. 
The  averages  for  the  three  horizons  were :  A,  18.6  mg. ;  B,  12.6  mg. ; 
and  C,  8.9  mg. 


30 


20 


10 


3  4  7  Soils 

Mg  N.  as  NH3  Produced 

Fig.  20a.     Graph  showing  ammonifieation  in  the  three  horizons  of  the  three 
samples  of  Altamont  clay  loam. 


10. 


7.5 
B 


\ 
\ 

\ 

V 

N 

\ 
\ 

W 

\ 

\ 

2.5 


3  4  7  Soils 

Mg  N.  Fixed 

Fig.  20b.     Graph  showing  nitrogen  fixation  in  milligrams  in  the  three  horizons 
of  the  three  samples  of  Altamont  clay  loam. 


Altamont  clay  loam. — As  regards  horizon  A  the  amount  of  am- 
monia produced  in  one  soil  is  three  times  that  in  the  lowest,  10  mg. 
nitrogen  and  33  mg.  nitrogen  as  ammonia,  with  8.9  mg.  as  the  average 
(table  30  and  fig.  20a).  The  amount  of  nitrogen  as  ammonia  pro- 
duced  in  the  B  horizon  averaged  12.6  mg.,  in  the  C  horizon  8.9  mg. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


417 


San  Joaquin  sandy  loam. — The  amount  of  ammonia  produced  in 
the  A  horizon  varied  between  30.4  mg.  of  nitrogen  and  57.1  mg.,  the 
average  was  40.2  mg.  (table  31  and  fig.  21a).  The  production  of 
ammonia,  in  milligrams  of  nitrogen,  by  the  B  samples  varied  between 
4.5  mg.  and  38.1  mg.,  with  20  mg.  as  the  average.  In  the  C  samples 
the  variation  was  nearly  as  great,  between  5.7  mg.  and  32  mg.,  with 
the  average  of  20.9  mg.    Thus  there  are  notable  variations  among  the 


12  13  17  18  21  26  Soils 

Mg  N.  as  NH3  produced 

Fig.  21a.     Graph  showing  ammonification  in  the  three  horizons  of  the  eight 
samples  of  San  Joaquin  sandy  loam. 


samples  of  this  type,  the  proportional  variation  being  very  great,  con- 
sidering the  three  horizons.  Possibly  the  reason  that  the  B  and  C 
horizons  are  so  divergent  from  the  surface  is  that  there  is  a  very 
marked  variation  in  the  texture  between  the  surface  horizon  and 
those  below  the  surface. 

Hanford  fine  sandy  loam. — The  variation  is  large  here  also  (table 
32,  fig.  22a),  the  largest  quantity  of  ammonia  produced  in  the  surface 
soil  is  twice  that  of  the  smallest  production,  72  mg.  and  35  mg.  The 
subsoil  variations,  in  a  general  way,  parallel  those  of  the  surface. 
The  average  production  of  ammonia  in  the  three  horizons  is  as  fol- 


418 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


lows:  A,  56.9  mg.  nitrogen;  B,  46.3  mg.  nitrogen;  and  C,  38.7  mg. 
nitrogen.  In  attempting  to  correlate  the  variations  in  ammonifying 
powers  with  the  known  variations  of  the  soils,  or  with  the  known  his- 
tories of  the  soils,  there  seem  to  be  no  relations  of  significance. 

The  Altamont  and  Diablo  types  are  about  alike  in  their  low  am- 
monifying power.  The  Hanford  and  San  Joaquin  are  both  higher 
and  nearer  to  each  other  than  to  the  two  heavy  types,  yet  the  Hanford 
is  noticeably  higher  than  the  San  Joaquin.  This  is  as  one  would  ex- 
pect, from  a  knowledge  of  the  soils  in  the  field.  Considering  the  types 
as  a  whole,  as  represented  by  the  A  horizon,  there  are  more  marked 
variations  between  the  types  than  between  the  samples  of  a  given  type 
though  the  variations  within  a  given  type  are  very  large. 


Average 


Table  29 — Ammonification 

Diablo  Clay  Adobe 

Milli 

grams  N  as 

NH3   Pi 

-oduced 

A 

A 

B 

C 

( 

Cultures 

Checks 
average 

Increase 

over 

checks 

Cultures 

Checks 
average 

Increase 

over 
checks 

r 
Cultures 

Increase 
Checks        over 
average     checks 

31.48 

28.58 

24.24 

40.32 

2.52 

33.38 

22.98 

2.28 

23.50 

14.99 

2.42       17.19 

19.81 

9.45 

8.41 

17.07 

1.68 

16.76 

9.84 

1.91 

7.73 

9.95 

1.05         8.13 

15.90 

11.55 

No  sample 

1.75 

14.15 

12.54 

1.54 

10.50 

12.33 

7.76 

12.33 

3 

2.11 

10.22 
18.63 

13.55 

2.07 

8.58 
12.58 

12.33 

2.03       10.30 
11.87 

Table  30 — Ammonification 
Altamont  Clay  Loam 


Milli; 

grams  N   as 

NH3  Pi 

reduced 

A 

A 

B 

A 

C 

Sample 

r 
Cultures 

Checks 
average 

>              > 

Increase 
over 
checks 

Cultures 

Checks 
average 

Increase 

over 
checks 

Cultures 

Checks 
average 

> 

Increase 

over 

checks 

3 

8.14 

6.97 

5.89 

10.58 

1.68 

7.68 

7.15 

1.40 

5.16 

4.91 

1.54 

3.86 

4 

19.75 

6.59 

5.41 

19.12 

2.66 

16.77 

6.67 

1.36 

5.27 

5.12 

1.19 

4.07 

7 

28.66 

19.66 

8.00 

27.53 

2.03 

26.06 

1 6.25 

1.75 

16.20 

12.37 

1.33 

8.95 

Average 

16.84 

8.88 

5.63 

1919] 


Pendleton:   A  Study  of  Soil  Types 


419 


Table  31 — Ammonification 
San  Joaquin  Sandy  Loam 
Milligrams  N   as  NH3  Produced 
B 


Sample 
10 

Cultures 
54.24 

Checks 
average 

Increase 

over 

checks 

r 

Cultures 
42.63 

Checks 
average 

Increase 

over 
checks 

r 

Cultures 
28.89 

1 
Checks 
average 

> 
ncrease 

over 
checks 

41.95 

1.72 

46.73 

36.11 

1.28 

38.09 

38.25 

1.59 

31.98 

11 

44.47 

7.47 

6.05 

73.23 

1.70 

57.15 

12.52 

1.81 

8.18 

6.78 

1.68 

4.78 

12 

44.48 

18.73 

10.91 

40.07 

1.56 

40.71 

21.81 

1.50 

18.77 

6.11 

1.14 

7.87 

13 

41.66 

5.41 

3.80 

45.04 

1.30 

42.50 

5.36 

0.86 

4.52 

15.17 

0.88 

8.60 

17 

30.19 

27.59 

No  sample 

33.88 

1.66 

30.37 

20.68 

1.51 

22.62 

18 

35.04 

30.56 

21.96 

35.24 

1.48 

33.66 

22.81 

1.30 

25.38 

16.92 

1.47 

17.97 

21 

34.44 

37.41 

25.72 

30.89 

1.48 

31.18 

37.74 

1.38 

36.19 

29.66 

1.42 

26.27 

26 

40.81 

7.50 

9.08 

1.64 

39.17 

8.41 

1.44 

6.51 

5.43 

1.54 

5.71 

A vera s 

:e 

40.18 

20.03 

12.89 

Table  32 — Ammonification 
Hanford  Fine  Sandy  Loam 

Milligrams  N   as  NH3  Produced 
B 


Sample 

Cultures 

Checks 
average 

Increase 

over 

checks 

r 
Cultures 

Checks 

average 

Horizons 

Increase 

over 
checks 

r 
Cultures 

Checks 
average 

Increase 

over 

checks 

14 

37.35 

27.96 

14.39 

43.57 

1.78 

38.68 

48.46 

1.46 

36.75 

41.70 

1.24 

26.80 

15 

33.11 

45.68 

59.90 

41.75 

1.75 

35.68 

48.38 

1.70 

45.33 

52.59 

1.62 

54.62 

16 

56.59 

44.08 

44.58 

56.77 

1.83 

54.85 

42.10 

1.61 

41.48 

52.10 

1.69 

46.65 

19 

52.92 

46.70 

24.56 

51.85 

1.47 

50.91 

38.92 

1.13 

41.68 

28.12 

1.24 

25.10 

20 

72.49 

45.49 

22.05 

74.21 

1.36 

71.99 

38.52 

1.03 

40.97 

30.35 

1.00 

25.20 

22 

64.92 

57.44 

46.08 

67.56 

1.75 

64.49 

55.34 

1.51 

54.88 

47.55 

1.60 

45.21 

23 

71.56 

50.84 

35.15 

68.66 

1.61 

68.50 

43.01 

1.37 

45.55 

35.23 

1.35 

33.84 

24 

65.02 

50.09 

37.56 

59.51 

1.50 

60.76 

46.54 

1.32 

46.99 

40.21 

1.33 

37.55 

25 

68.20 

69.29 

61.01 

67.29 

1.43 

66.31 

60.03 

1.25 

63.41 

47.70 

1.22 

53.13 

Average 

56.91 

46.34 

38.67 

420 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Nitrogen  Fixations 

Diablo  clay  adobe. — This  type  shows  the  highest  quantity  of  nitro- 
gen fixed,  9.6  m'g.,  with  the  subsoil  quantities,  much  lower  than  the 
surface.  The  variation  within  the  type  is  seen  to  be  the  largest  of  that 
in  any  of  the  types. 

Altamont  clay  loam. — The  surface  samples  have  1.0,  4.7,  and  9.1 
mg.  nitrogen  (table  34  and  fig.  20b).  The  soils  shows  a  wide  diver- 
gence between  the  surface  samples  and  between  the  surface  and  sub- 
soils.   This  is  to  be  expected  in  the  heavier  soils. 


7.5 
C 


2.3 


\ 

\       7* 
\ 
\ 

\      \ 

\ 

\ 

\ 

X 

______  _^^+ 

^ 

10 


11 


12 


13  17 

Mg  N.  Fixed 


IS 


21 


26  Soils 


Fig.   21b.     Graph    showing   nitrogen   fixation   in   the    three   horizons    of   the 
eight  samples  of  San  Joaquin  sandy  loam. 


San  Joaquin  sandy  loam. — The  quantity  fixed  in  the  A  horizon 
(table  35  and  fig.  21b)  is  small  and  quite  variable.  It  is  between 
nothing  and  5.5  mg.,  with  the  average  of  1.9  mg.  Instead  of  nitrogen 
fixation  denitrification  took  place  in  a  number  of  cases,  especially  in 
horizon  C.  Considering  the  wide  variation  in  textures  of  the  horizons, 
it  is  rather  odd  that  there  should  not  be  a  greater  variation  between 
the  soils  from  the  various  depths. 

Han  ford  fine  sandy  loam. — The  amount  of  nitrogen  fixed  by  the 
surface  soil  (table  36,  and  fig.  22b)  averages  much  higher,  5.7  mg., 
than  that  in  the  San  Joaquin  sandy  loam,  though  the  range  of  varia- 
tion is  about  the  same.  It  is  noticeable  that  the  amounts  of  nitrogen 
fixed  by  the  B  and  C  horizons  of  the  soils  nos.  14  and  19  are  much 


28  All  of  the  figures  on  nitrogen  fixation  refer  to  the  milligrams  of  nitrogen 
fixed  per  gram  of  mannite  in  50  grams  of  soil  (table  33  and  figs.  9-13). 


1919] 


Pendleton :   A  Study  of  Soil  Types 


421 


less  (even  to  denitrification)  absolutely  and  relatively  as  compared 
with  the  surface  horizons,  than  the  amount  fixed  by  the  B  and  C 
horizons  of  the  soils  nos.  20  to  25  inclusive. 

Comparing  the  nitrogen  fixation  of  the  various  types,  there  seem 
to  be  no  characteristic  differences  between  the  heavy  Altamont  and 
Diablo  types,  while  the  lighter  Hanford  and  San  Joaquin  types  are 
considerably  different  from  each  other.  As  a  whole  there  is  but  a  fair 
degree  of  similarity  between  the  samples  of  a  given  type.  The  degree 
of  variation  within  types  is  large. 


Table 

33 — Nitrogen  Fixation 
Diablo  Clay  Adobe 

Millisri 

ams   N  per 

gram   of 

mannite 

A 

A 

B 

A 

C 

A 

Sample 

f 
Cultures 

Checks 
average 

Increase 

over 

checks 

Cultures 

Checks 
average 

Increase 
over 

checks 

r 

Cultures 

Checks 
average 

Increase 

over 

checks 

1 

60.25 

31.52 

22.77 

63.40 

52.22 

9.60 

29.56 

34.67 

-4.13 

24.87 

28.61 

-4.79 

2 

55.34 

32.92 

30.47 

49.39 

45.88 

6.48 

38.18 

33.80 

1.75 

32.22 

29.77 

1.57 

5 

48.68 

35.73 

No  sample 

48.68 

41.92 

6.76 

37.12 

32.39 

4.03 

6 

45.88 

39.64 

35.02 

46.86 

58.49 

-12.12 

42.72 

50.77 

-9.59 

39.01 

39.05 

-2.03 

Average 

4.71 

1.44 

0.52 

Table  34 — Nitrogen  Fixation 
Altamont  Clay  Loam 

Milligrams   N  fixed  per  gram  of   mannite 
B 


Sample 

Cultures 

Checks 
average 

Increase 
over 

checks 

r 
Cultures 

Checks 
average 

Increase 

over 
checks 

r 
Cultures 

Checks 
average 

Increase 

over 

checks 

3 

71.26 

49.04 

37.13 

70.40 

61.71 

9.12 

51.84 

43.78 

6.66 

38.51 

33.76  . 

4.06 

4 

60.25 

28.02 

20.31 

52.19 

51.49 

4.73 

27.32 

26.48 

1.19 

21.01 

20.48 

0.18 

7 

52.95 

37.75 

30.81 

53.44 

52.12 

1.08 

37.40 

36.60 

1.00 

27.18 

29.94 

-0.94 

Average 

4.98 

2.95 

1.41 

422  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


7d 


:.o 


40 


30 


20 


10 


. 

/^/ 

1 

1 
1 

N                        / 

N                  / 

S             / 

/ 

\ 
\ 

/ 

/'« 

/        / 

t 

1 

1 

1/ 

/         \ 

\ 
\ 

— *— 

/ 
/    , 

/    / 

X 

\ 

\ 
\ 
N 
\ 

-— -"" 

/      / 

/ 
/ 

/ 
/ 

/ 
/ 
/ 

\ 

\ 
\ 
\ 

\ 
\ 

/ 
/ 
/ 
/ 

/ 

/ 

\ 

\ 
\ 
\ 

^" 

/ 

/ 

< 

\ 
\ 

> 



/ 
/ 

- 

15 


16 


23 


24 


19  20  22 

Mg  N.  as  NH3  produced 
Fig.  22a.     Graph  showing  ammonification  in  the  three  horizons  of  the  nine 
samples  of  Hanford  fine  sandy  loam. 


26  Soils 


10 


7.5 


2.5 


// 

\\ 

\\ 

/ 

>< 

s 

// 

/ 
/ 
/ 

1 

l  \ 


23 


21 


15  16  19  20  22 

Mm  N.  Fixed 
Pig.  22b.     Graph  showing  nitrogen  fixation  in  the  three  horizons  of  the  nine 
sum  pies  of  Hanford  fine  sandy  loam. 


25  Soils 


1919] 


Pendleton:   A  Study  of  Soil  Types 


423 


Table  35 — Nitrogen  Fixation 
San  Joaquin  Sandy  Loam 

Milligrams  N  fixed  per  gram  of  mannite 


A 

A 

B 

A 

C 

Sample 

Cultures 

Checks 
average 

Increase 
over 
checks 

r 
Cultures 

Checks 
average 

Increase 

over 
checks 

r 
Cultures 

Checks 
average 

Increasi 

over 

checks 

10 

25.01 

17.16 

15.83 

23.47 

18.73 

5.51 

16.67 

13.59 

3.32 

18.14 

10.33 

6.65 

11 

27.25 

22.91 

21.72 

31.87 

25.15 

4.41 

22.84 

21.78 

1.09 

22.00 

19.43 

2.43 

12 

25.85 

20.17 

18.98 

23.82 

23.26 

1.57 

17.09 

16.56 

2.07 

20.10 

20.41 

-0.87 

13 

22.77 

18.49 

13.31 

21.58 

20.00 

2.17 

17.86 

20.21 

-2.04 

14.50 

16.35 

-2.45 

17 

13.52 
13.45 

9.46 
10.23 

No  samp] 

[e 

18 

15.55 

8.76 

9.18 

13.24 

13.73 

0.66 

8.20 

8.09 

0.39 

11.42 

9.74 

0.56 

21 

14.85 

7.98 

6.58 

16.11 

14.50 

0.98 

6.44 

5.96 

1.25 

7.28 

7.01 

-0.07 

26 

19.54 

12.61 

7.14 

19.34 

20.34 

-0.94 

12.82 

13.34 

-0.72 

7.36 

8.24 

-0.99 

Av 

erage 

1.91 

1.09 

1.20 

Table  36 — Nitrogen  Fixation 
Hanford  Fine  Sandy  Loam 


Milligrams 

N  fixed  per  gram 

of  mannite 

A 

A 

B 

C 

A 

Sample 

r 
Cultures 

Checks 
average 

Increase 
over 
checks 

r 
Cultures 

Checks 
average 

^ 

Increase 

over 
checks 

r 
Cultures 

Checks 
average 

Increase 

over 

checks 

14 

71.52 

41.61 

31.10 

63.05 

59.61 

7.67 

41.69 

41.01 

0.64 

30.19 

29.07 

1.57 

15 

38.18 

22.07 

12.40 

29.56 

26.55 

7.32 

21.09 

20.12 

1.46 

14.08 

13.87 

-0.63 

16 

30.33 

16.46 

9.67 

32.92 

27.84 

3.78 

16.04 

14.85 

1.40 

8.97 

10.61 

-1.29 

19 

25.56 

14.43 

11.77 

26.41 

22.49 

4.49 

13.59 

12.29 

1.72 

12.33 

11.80 

-0.25 

20 

38.04 

22.84 

17.09 

38.11 

29.66 

8.41 

23.61 

16.39 

6.83 

20.60 

11.52 

7.32 

22 

35.59 

22.20 

17.30 

31.80 

29.17 

4.52 

23.40 

17.23 

5.57 

16.46 

11.87 

5.0T 

23 

38.95 

19.19 

11.90 

43.57 

36.10 

5.16 

20.25 

14.57 

5.15 

11.98 

8.90 

3.04 

24 

28.79 

19.89 

18.52 

34.61 

25.67 

6.03 

21.52 

16.95 

3.75 

17.51 

13.91 

4.11 

25 

26.55 

17.86 

15.55 

26.41 

22.70 

3.78 

17.93 

15.51 

2.38 

13.87 

11.31 

3.41 

Average 

5.69 

3.21 

2.27 

424 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.3 


NITRIPICATION29 

The  most  noticeable  thing  about  the  nitrification  results  is  the 
very  wide  range  of  variation  in  the  various  representatives  of  the 
Hanford  fine  sandy  loam  as  compared  with  the  quite  uniform  and 
consistent  results  obtained  with  the  other  types. 

Diablo  clay  adobe. — The  percentage  of  nitrogen  nitrified  (table 
37,  38,  and  fig.  23)  is  uniformly  low.  The  B  samples  showed  a  less 
vigorous  nitrifying  flora  (except  in  the  case  of  no.  6)  than  the  sur- 
face ones.     Dried  blood  in  the  quantities  used  seems  to  depress  the 


A  S.  N.+ Cottonseed  Meal 


-A  S.  N.+  (NH4)2S04 


A  S.  N.  +  Dried  Blood 
A  Soil  Nitrogen 


12  5  6  Soils 

Percentages  of  N.  Nitrified 

Fig.   23.     Graph   showing  the  percentages   of   nitrogen   in   various   nitrogen 
containing  materials  nitrified  in  the  four  samples  of  the  Diablo  clay  adobe. 


normal  activity  (A  horizon  average  0.81%),  while  the  (NH4)2S04 
(A  horizon  average  3.03%)  and  the  cottonseed  meal  (A  horizon 
average  2.91%),  as  compared  with  the  incubated  control  tend  to  in- 
crease the  percentage  of  nitrogen  nitrified.  It  should  be  kept  in  mind 
that  an  absolute  increase  in  the  nitrogen  content  may  accompany  a 
decrease  in  the  percentage,  due  to  the  greatly  increased  amount  of 
nitrogen  present  after  the  addition  of  a  nitrogenous  substance.  The 
variation  of  the  samples  within  this  type  is  very  moderate  as  compared 
with  the  San  Joaquin  and  Hanford  types. 


29  The  figures  used  in  the  discussion  shows  the  percentages  of  the  nitrogen  in 
the  cultures  which  were  nitrified.  There  are  two  tables  for  the  samples  of  each 
type.  The  percentages  of  nitrogen  nitrified  are  rearranged  in  a  second  table  for 
greater  ease  in  comparing  results. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


425 


Altamont  clay  loam. — The  percentages  of  nitrogen  nitrified  (tables 
39  and  40,  fig.  24)  are  as  a  whole  lower  than  in  the  Diablo  soils.  A 
similar  relative  effect  of  the  several  nitrogenous  materials  is  seen,  for 
(NH4)2S04  is  first,  cottonseed  meal,  second,  the  soil's  own  nitrogen 
third,  and  dried  blood  fourth  in  the  percentages  of  nitrates  produced. 
As  in  the  Diablo  soils  the  variation  is  not  great  from  soil  to  soil. 

San  Joaquin  sandy  loam. — A  wide  range  of  variation  (tables  41, 
42,  and  fig.  25),  from  1.2%  £o  4.5%,  is  found  in  the  incubated  control, 
possibly  due,  in  part,  to  the  considerable  variations  in  the  physical 
nature  of  the  samples.     The  relative  action  of  the  nitrogenous  ma- 


A  S.  N.+  (NH4)2S04 
A  S.  N.  +Cottonseed  Meal 
A  Soil  Nitrogen 
A  S.  N.  + Dried  Blood 
4  7  Soils 

Percentages  of  N.  Nitrified 
Fig.   24.     Graph   showing   the   percentages   of   nitrogen    in   various   nitrogen 
containing  materials  nitrified  in  the  three  samples  of  the  Altamont  clay  loam. 


terials  in  the  soils  of  the  San  Joaquin  samples  as  compared  with  that 
in  the  Diablo  and  Altamont  soils  is  well  shown  by  the  following  aver- 
ages of  the  A  horizon:  dried  blood  had  0.02%.  cottonseed  meal  had 
0.33%,  and  ammonium  sulfate  had  0.56%  of  the  nitrogen  nitrified, 
while  the  incubated  control  had  2.47%  nitrified.  The  soils  are  normally 
low  in  nitrogen,  and  this,  together  with  the  poor  physical  condition, 
made  an  unfavorable  medium  for  any  bacterial  activity.  This  applies 
especially  to  horizons  B  and  C. 

Han  ford  fine  sandy  loam. — This  is  by  far  the  most  inexplicable 
set  of  results  in  the  nitrification  studies  (tables  43,  44,  and  fig.  26). 
The  physical  nature  of  this  type  is  admirably  suited  for  bacteriological 
tumbler  cultures,  the  soil  being  friable,  not  puddling  readily,  and 
while  in  the  incubator  may  be  kept  at  the  approximately  optimum 
moisture  content  with  little  difficulty.     This  property  is  fairly  con- 


426  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

stant  throughout  all  the  samples  (except  no.  14)  and  cannot  well 
be  supposed  to  affect  the  results  greatly.  No.  14  has  a  low  nitrifying 
power  throughout,  but  it  is  not  representative  of  the  type,  for  it  is 
heavier  in  texture  than  the  rest.  Moreover,  it  had  been  submerged 
by  river  overflows  shortly  before  the  collection  of  the  sample.  One 
would  expect  these  factors  to  influence  the  numbers  and  the  activity 
of  the  bacterial  flora.  There  is  but  little  similarity  in  the  way  the 
different  samples  of  the  A  or  B  horizons  behave  toward  any  given 


/ 

-— _ 

\ 

/ 

/ 

\ 

\ 

/ 

\ 

/ 

/ 

\ 

/ 

/ 

\ 

\ 

/ 

/ 

\ 

^ 

v^ 

\ 

""•N 

'^^" 

A.  Soil  Nitrogen 


A.  S.  N.+  (NHO2SO4 


S.  N.  -{-Cottonseed  Meal 


10 


12 


21 


26  Soils 


13  17  18 

Percentages  of  N.  Nitrified 

Fig.  25.  Graph  showing  the  percentages  of  nitrogen  in  various  nitrogen 
containing  materials  nitrified  in  the  eight  samples  of  the  San  Joaquin  sandy 
loam. 


nitrogen  containing  material.  Variations  from  1%  to  50%,  from 
0%  to  14%,  from  4.5%  to  8%,  or  from  15%  to  15.5%  from  soil  to 
soil,  without  regularity,  give  slight  basis  for  generalizations.  The 
average  effect  of  the  A  horizon  samples  of  the  Hanford  fine  sandy 
loam  as  regards  the  several  nitrogenous  materials  is  as  follows :  dried 
blood,  5.62%;  cottonseed  meal,  13.72%;  ammonium  sulfate,  3.29%; 
incubated  control,  1.55%.  In  a  general  way  there  is  a  similarity 
between  the  effects  of  a  given  nitrogen  containing  material  on  the 
surface  sample,  and  on  the  B  horizon.  This  should  be  so,  since  these 
soils  are  very  deep  and  uniform  in  texture.  However,  in  the  C 
horizon   there  were  still   greater  decreases  in  the  bacterial  activity. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


427 


As  regards  nitrification  in  general  there  is  difficulty  in  showing 
any  greater  resemblance  between  the  samples  of  a  type  than  there  is 
from  type  to  type.  In  certain  features,  however,  the  types  are  some- 
what distinct :  ( 1 )  The  relation  of  the  nitrification  of  the  soil 's  own 
nitrogen  to  the  soil's  action  upon  added  nitrogen  is  rather  distinct 
for  the  types.  The  normal  soil  in  the  San  Joaquin  type  gave  a  much 
larger  per  cent  of  nitrogen  than  did  the  soil  plus  the  added  nitrogen 
containing  materials.  In  the  Diablo  type  (fig.  25)  the  normal  soil 
was  about  midway  in  its  production  as  compared  with  the  soils  to 
which  the  nitrogenous  materials  were  added.  In  the  Hanford  fine 
sandy  loam  the  normal  soils  gave  a  much  lower  percentage  nitrifica- 
tion than  in  the  greater  number  of  instances  where  the  soils  were 
treated  with  nitrogenous  materials.  (2)  The  relative  nitrification  of 
the  various  nitrogenous  materials  is  somewhat  distinct  for  the  types. 
The  Diablo,  Altamont,  and  San  Joaquin  show  the  ammonium  sulfate 
first,  with  the  cottonseed  meal  second,  and  the  dried  blood  third.  The 
Hanford  type  shows  cottonseed  meal  first,  with  dried  blood  second  and 
ammonium  sulfate  third. 


Table  37 — Nitrification 
Diablo  Clay  Adobe 


Soil  nitrogen 

a 

Soil  nitrogen  and 
ammonium  sulfate 

A 

Soil  nitrogen  : 
dried  blood 

A 

and 

Soil  nitrogen  and 
cottonseed  meal 

A 

Sample 

6  si 

11 

o 
w     . 

a.  bfl 

'as 

_,  o 
Eh 

> 

si 

6  si 

®tJ 

«  s 

u  $ 

0) 

<k  si 
_  o 

n  <° 

o.S 

s>d£ 

O  li 

o  si 

to     • 
a>  Suo 

o.S 

6H 

O  U 

o  si 

<Dntf 

If 

a>  si 

£•1 
«  w 

o.S 

za 

g'5 

1-A 

0.90 

104.43 

0.86 

5.35 

146.82 

3.65 

2.20 

347.22 

0.63 

5.00 

198.42 

2.50 

1-B 

0.28 

93.34 

0.30 

0.77 

135.74 

0.57 

Tr. 

336.14 

Tr. 

187.34 

1-C 

0.19 

57.22 

0.33 

0.25 

99.62 

0.25 

0.07 

300.02 

0.02 

0.16 

151.22 

2-A 

0.47 

91.76 

0.51 

3.47 

134.16 

2.58 

4.07 

334.56 

1.22 

6.82 

185.76 

3.77 

2-B 

0.33 

67.60 

0.49 

1.17 

110.00 

1.06 

0.08 

310.40 

0.19 

161.60 

0.12 

2-C 

0.59 

59.54 

0.29 

101.94 

0.80 

302.34 

0.80 

153.54 

5-A 

0.47 

83.82 

0.56 

3.81 

126.22 

3.02 

1.66 

326.62 

0.51 

3.76 

177.82 

2.12 

5-B 

0.36 

64.78 

0.56 

0.42 

107.18 

0.39 

0.19 

307.58 

0.06 

0.97 

158.78 

0.61 

6-A  0.59  116.58  0.51 
6-B  1.65  101.54  1.63 
6-C       0.96       78.10     1.23 


4.58  158.98  2.88 

3.00  143.94  2.08 

1.01  120.50  0.84 


3.13  359.38  0.87 
1.19  344.34  0.35 
0.37  320.90  0.01 


6.88  210.58  3.26 
4.55  195.54  2.32 
0.47  172.10  0.27 


I 


428 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


55 

oil 

1 

\ 

4o 

\ 

\ 

40 

\ 

\ 

35 

\ 

1 

o! ) 

\ 

1 

J.J 

\ 

1 

20 

\ 

1 

1.) 

\ 

1 

! 

\ 

Jo 

\ 

\ 

s 

5 

-^ 

s 

/  \ 

/        \ 

s 

s  . 

-v 

15 


L6 


23 


24 


Fig.  26. 
containing 
loam. 


17  20  22 

Percentages  of  N.  Nitrified 

Graph   showing   the   percentages   of   nitrogen   in   various   nitrogen 
materials  nitrified  in  the  nine  samples  of  the  Hanford  fine  sandy 


A  S.  N.  +  Cottonseed 
Meal 


^  A  S.  N.+  (NH4)2S04 
A  Soil  Nitrogen 
A  S.  N.  +  Dried  Blood 

25  Soils 


1919] 


Pendleton:   A  Study  of  Soil  Types 


429 


Sample 
1 
2 
5 
6 
Average 


A 
0.86 
0.51 
0.56 
0.51 
0.61 


Table  38 — Nitrification — Percentages  of  Nitrogen  Nitrified 

Diablo  Clay  Adobe 

Soil  nitrogen  and  Soil  nitrogen  Soil  nitrogen 

Soil  nitrogen  ammonium  sulfate  and  dried  blood  cottonseed  meal 

— * ,  , a *         , a ;  , a * 

BC  ABC  ABC  ABC 

0.30     0.33  3.65     0.57     0.25  0.63      0.02  2.50      

0.49      2.58     1.06      1.22      3.77     0.12      

0.56      3.02     0.39      0.51     0.06      2.12     0.61      

1.63     1.23  2.88     2.08     0.84  0.87     0.35     0.01  3.26     2.32     0.27 

0.74     0.52  3.03     1.02     0.36  0.81     0.10     0.01  2.91     0.76     0.09 


Table  39 — Nitrification 
Altamont  Clay  Loam 


So 

il  nitrogei 

A 

i 

Soil  nitrogen  and 
ammonium  sulfate 

Soil  nitrogen  and 
dried  blood 

A 

Soil  nitrogen  and 
cottonseed  meal 

A 

6  &i 

CO     • 

eg 

u  S 

CD 

a>  be 

6  tx 

CD 

CD    fafi 

6  tx 

CD 

tffl 
0-  fcJD 

$ 

J--T3 

Sample 

If 

_   O 
^3  cc 

o  h 

®T3 

_  o 

O  U 

1* 

Is 

_  o 
Is  M 
o.S 

Eh 

o  u 

IS 

^_  o 

•  ©.a 

3-A 

0.60 

123.42 

0.49 

4.12 

165.82 

2.49 

1.17 

366.22 

0.32 

3.57 

217.42 

1.64 

3-B 

0.04 

87.56 

0.05 

0.39 

129.96 

0.32 

0.18 

330.36 

0.03 

181.56 

3-C 

0.27 

67.52 

0.40 

0.20 

109.92 

0.18 

0.10 

310.32 

0.10 

161.52 

4-A 

1.30 

102.58 

1.27 

2.95 

144.98 

2.05 

2.34 

345.38 

0.68 

4.83 

196.58 

2.46 

4-B 

0.45 

52.96 

0.85 

95.36 

0.10 

295.76 

146.96 

4-C 

40.96 

83.36 

283.76 

0.20 

134.96 

0.15 

7-A 

0.50 

104.24 

0.48 

1.35 

146.64 

0.93 

0.40 

347.04 

0.12 

1.27 

198.24 

0.64 

7-B 

0.25 

73.20 

0.34 

0.32 

115.60 

0.28 

316.00 

167.20 

7-C 

59.88 

102.28 

302.68 

153.88 

Table  40 — Nitrification — Percentages  of  Nitrogen  Nitrified 
Altamont  Clay  Loam 


Soil  nitrogen 
ABC 

Soil  nitrogen  and 
ammonium  sulfate 

A 

Soil 
and  d: 

nitrogen 
ried  blood 

Soil  nitrogen  and 
cottonseed  meal 

A 

Sample 

A 

B 

^ 

c 

A 

B          C 

A              B 

C 

3 

0.49 

0.05 

0.40 

2.49 

0.32 

0.18 

0.32 

1.64      

4 

1.27 

0.85 

2.05 

0.68 

2.46      

0.15 

7 

0.48 

0.34 

0.93 

0.28 

0.12 

0.64      

Average 

0.75 

0.41 

0.13 

1.82 

0.20 

0.06 

0.37 

1.58      

0.05 

430 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table  41 — Nitrification 
San  Joaquin  Sandy  Loam 


Soil  nitrogen 

Soil  nitrogen  and 
ammonium  sulfate 

Soil 

nitrogen  and 
Iried  blood 

Soil  nitrogen  and 
cottonseed  meal 

A 

Sample 

10- A 

O  bi 

0.52 

a3 
a>  bi 

&a 

_  o 

n  * 

Eh 

37.46 

o  u 

u  *> 

1.4 

o  si 

s  a 

0.24 

03      • 
a>  bSt 

'aa 
|.a 

122.26 

%8 

y 

p  U 

0.2 

6  si 

is 

0.06 

Xfl       • 

<a  he 

'as 
©.a 

En 
302.46 

Sol 

O   U 
I" 

0.02 

6  m 

^a 
£% 

0.10 

<v  bt 

£a 

_  o 

|.S 
121.46 

y 

p  ^ 

I* 

0.08 

10-B 

0.23 

27.18 

0.9 

0.08 

111.98 

0.07 

292.18 

111.18 

10-C 

0.07 

20.66 

0.3 

0.06 

105.46 

0.06 

285.66 

0.08 

104.66 

0.08 

11-A 

1.25 

50.30 

2.5 

0.50 

135.10 

0.4 

0.27 

315.30 

0.09 

0.95 

134.30 

0.7 

11-B 

41.56 

0.02 

126.36 

0.08 

306.56 

0.03 

0.02 

125.56 

11-C 

0.14 

38.86 

0.4 

Tr. 

123.66 

Tr. 

303.86 

Tr. 

122.86 

12- A 

0.80 

46.52 

1.7 

0.55 

131.32 

0.4 

0.09 

311.52 

0.03 

2.05 

130.52 

1.6 

12-B 

0.18 

33.12 

0.5 

0.11 

117.92 

0.09 

Tr. 

298.12 

Tr. 

117.12 

12-C 

0.14 

40.82 

0.3 

0.06 

125.62 

0.06 

305.82 

0.06 

124.82 

13-A 

0.49 

40.00 

1.2 

0.59 

124.80 

0.5 

0.07 

305.00 

0.02 

0.10 

124.00 

0.08 

13-B 

0.06 

40.41 

0.10 

125.21 

0.08 

0.21 

305.41 

0.69 

124.41 

13-C 

0.35 

32.70 

1.1 

0.25 

117.50 

0.2 

0.00 

297.70 

0.96 

116.70 

17-A 

0.54 

28.92 

1.9 

0.45 

113.72 

0.4 

Tr. 

293.92 

112.92 

17-B 

18.42 

103.22 

Tr. 

283.42 

0.08 

102.42 

0.08 

18- A 

1.25 

27.46 

4.5 

1.00 

112.26 

0.9 

292.46 

Tr. 

111.46 

18-B 

Tr. 

16.18 

Tr. 

100.98 

Tr. 

281.18 

Tr. 

100.18 

18-C 

19.48 

0.10 

104.28 

1.0 

284.48 

103.48 

21-A 

1.25 

29.00 

4.3 

1.30 

113.80 

1.1 

Tr. 

294.00 

0.13 

113.00 

21-B 

11.92 

96.72 

276.92 

95.92 

21-C 

0.01 

14.02 

0.01 

98.82 

0.01 

0.15 

279.02 

0.15 

98.02 

26-A 

0.95 

40.68 

2.3 

0.80 

125.48 

0.6 

Tr. 

305.68 

0.19 

124.68 

0.10 

26-B 

Tr. 

26.28 

111.48 

Tr. 

291.68 

Tr. 

110.68 

26-C 

16.48 

101.28 

Tr. 

281.48 

100.48 

Table  42 — Nitrification — Percentages  of  Nitrogen  Nitrified 
San  Joaquin  Sandy  Loam 


Soil 

nitrogen 

Soil  nitrogen  and 
ammonium  sulfate 

Soil  nitrogen 
and  dried  blood 

A 

Soil  nitrogen  and 
cottonseed  meal 

Sample 

r 

A 

B 

c    N 

'     A 

B 

c    ' 

r 
A 

B          C 

A 

B 

c' 

10 

1.4 

0.9 

0.3 

0.2 

0.07 

0.06 

0.02 

0.08 

0.08 

11 

2.5 

0.4 

0.4 

0.09 

0.03      

0.7 

12 

1.7 

0.5 

0.3 

0.4 

0.09 

0.03 

1.6 

13 

1.2 

1.1 

0.5 

0.08 

0.20 

0.02 

0.08 

17 

1.9 

0.4 

0.08 

18 

4.5 

0.9 

1.00 

21 

4.3 

1.1 

0.01 

0.10 

26 

2.3 

0.6 

0.1 

Average 

2.47 

0.17 

0.3 

0.56 

0.03 

0.18 

0.02 

0.33 

0.01 

0.01 

1919] 


Pendleton:   A  Study  of  Soil  Types 


431 


Table  43 — Nitrification 
Eanford  Fine  Sandy  Loam 


Soil  nitrogen 

Soil  nitrogen  and 
ammonium  sulfate 

A 

Soil  nitrogen  and 
dried  blood 

A 

Soil  nitrogen  and 
cottonseed  meal 

r   - 
o  &i 

c 

ce     . 

O  bE 

O  bi 

c 

CO      . 

as 

o  bi 

^  a 

$  bi) 

t — 

O  M 

w 
<U  bJD 

fl'g 

|§ 

Sample     2 

_  o 
o.S 

&S 

O    S-, 

©T3 

o.S 
Eh 

"S  © 

£3 

o.S 
Eh 

I5 

OT3 

11 
1* 

o.S 

Eh 

O   U 

14-A    0.20 

119.22 



0.25 

161.62 

0.1 

10.35 

254.22 

4.1 

1.85 

166.22 

i.i 

14-B    0.45 

82.02 

0.42 

124.42 

0.23 

217.02 

0.48 

129.02 

14-C    0.07 

58.14 

0.1 

0.75 

100.54 

0.7 

0.15 

193.14 

0.1 

0.10 

105.14 

0.1 

15- A  1.45 

53.10 

2.7 

3.20 

95.50 

.  3.4 

0.40 

188.10 

0.2 

50.85 

100.10 

50.8 

15-B  0.18 

40.24 

0.4 

0.19 

82.64 

0.2 

Tr. 

175.24 

1.42 

87.24 

1.6 

15-C   0.03 

27.74 

0.1 

0.01 

70.14 

Tr. 

162.74 

0.03 

74.74 

16-A  0.87 

55.68 

1.6 

2.50 

98.08 

2.5 

0.50 

190.68 

0.2 

4.60 

102.68 

4.5 

16-B  0.11 

29.70 

0.4 

0.08 

72.10 

0.1 

Tr. 

164.70 

3.70 

76.70 

4.8 

16-C   0.03 

21.22 

0.1 

Tr. 

63.62 

0.05 

156.22 

0.17 

68.22 

0.2 

19-A  1.00 

44.98 

2.2 

2.03 

87.38 

2.3 

0.21 

179.98 

0.1 

7.48 

91.98 

8.1 

19-B  0.08 

24.58 

0.3 

0.12 

66.98 

0.2 

159.58 

0.20 

71.58 

0.3 

19-C  0.16 

23.60 

0.7 

0.15 

66.00 

0.2 

Tr. 

158.60 

0.20 

70.60 

0.3 

20-A  0.77 

59.32 

1.3 

1.24 

101.72 

1.2 

27.39 

194.32 

14.1 

6.19 

104.32 

5.9 

20-B  0.12 

32.78 

0.4 

0.11 

75.18 

0.1 

15.50 

167.78 

9.2 

1.45 

77.78 

1.9 

20-C     

23.04 

65.44 

158.04 

0.07 

68.04 

0.1 

22-A  0.83 

58.34 

1.4 

6.48 

100.74 

6.4 

2.68 

193.34 

1.4 

13.58 

103.34 

13.1 

22-B  0.27 

34.46 

0.8 

0.26 

76.86 

0.3 

0.04 

169.46 

0.02 

1.91 

79.46 

2.4 

22-C    0.85 

23.74 

3.6 

5.40 

66.14 

8.2 

0.52 

158.74 

0.3 

2.50 

68.74 

3.6 

23-A  1.45 

72.20 

2.0 

8.95 

114.6 

7.8 

37.25 

207.20 

17.9 

18.25 

117.20 

15.5 

23-B   0.75 

29.14 

2.6 

8.90 

71.54 

12.5 

0.47 

164.14 

0.3 

2.65 

74.14 

3.6 

23-C    0.32 

17.80 

1.8 

12.40 

60.20 

20.6 

0.02 

152.80 

0.01 

1.30 

62.80 

2.1 

24-A  0.80 

51.34 

1.6 

4.10 

93.74 

4.4 

22.35 

186.34 

11.9 

14.35 

96.34 

14.9 

24-B  0.03 

33.90 

0.1 

0.36 

76.30 

0.5 

0.46 

168.90 

0.3 

5.91 

78.90 

7.5 

24-C    0.33 

27.82 

1.1 

0.33 

70.22 

0.5 

0.63 

162.82 

0.4 

0.73 

72.82 

1.0 

2 5- A  0.56 

45.40 

1.2 

1.30 

87.80 

1.5 

1.30 

180.40 

0.7 

8.65 

90.40 

9.6 

25-B  0.32 

31.01 

1.0 

0.32 

73.41 

0.4 

Tr. 

166.01 

0.05 

76.01 

0.06 

25-C  0.11 

22.62 

0.5 

0.16 

65.02 

0.2 

Tr. 

157.62 

Tr. 

67.62 

Table  44 — Nitrification — Percentages  of  Nitrogen  Nitrified 
Hanford  Fine  Sandy  Loam 


Soil  nitrogen 

Soil  nitrogen  and 
ammonium  sulfate 

Soil  nitrogen 
and  dried  blood 

Soil  nitrogen  and 
cottonseed  meal 

Sample 

A 

B 

C 

f 

A 

B 

C    * 

'    A 

B 

cN 

r  " 
A 

B 

C 

14 

0.1 

0.1 

0.7 

4.1 

0.1 

1.1 

0.1 

15 

2.7 

0.4 

0.1 

3.4 

0.2 

0.2 

4.5 

4.8 

0.2 

16 

1.6 

0.4 

0.1 

2.5 

0.1 

0.2 



4.5 

4.8 

0.2 

19 

2.2 

0.3 

0.7 

2.3 

0.2 

0.2 

0.1 

8.1 

0.3 

0.3 

20 

1.3 

0.4 

1.2 

0.1 

14.1 

9.2 

5.9 

1.9 

0.1 

22 

1.4 

0.8 

3.6 

6.4 

0.3 

8.2 

1.4 

0.02 

0.3 

13.1 

2.4 

3.6 

23 

2.0 

2.6 

1.8 

7.8 

12.5 

20.6 

17.9 

0.3 

0.01 

15.5 

3.6 

2.1 

24 

1.6 

0.1 

1.1 

4.4 

0.5 

0.5 

11.9 

0.3 

0.4 

14.9 

7.5 

1.0 

25 

1.2 

1.0 

0.5 

1.5 

0.4 

0.2 

0.7 

9.6 

0.06 

Average 

1.55 

0.66 

0.88 

3.29 

1.59 

3.38 

5.62 

1.09 

0.09 

13.72 

2.55 

0.82 

432  University  of  California  Publications  in  Agricultural  Sciences        [Vol.3 


Greenhouse  Data 

There  are  objections  to  all  greenhouse  work  due  to  somewhat  un- 
natural conditions  for  the  usual  indicator  crops,  the  lack  of  a  normal 
water  supply,  the  small  amount  of  root  space,  etc.  Crowding  of  the 
pots  is  also  apt  to  cause  variations.  Even  the  slight  change  in  the  loca- 
tion of  a  pot  on  the  bench  will  affect  the  growth  of  plants,  as  some  of 
the  elaborate  precautions  for  moving  the  pots  daily,  and  in  a  given 
order,  testify.  The  outstanding  advantage  of  greenhouse  work  is  that 
with  a  given  indicator  crop  a  group  of  soils,  or  soil  conditions,  may  be 
compared  under  very  similar  conditions. 

In  the  present  case,  the  leaks  in  the  sash  allowed  rain  water  to  fall 
into  some  of  the  pots  to  a  considerable  extent.  The  pots  so  affected 
showed  a  poorer  growth  in  the  cases  of  the  heavy  Altamont  and 
Diablo  samples,  where  the  soil  was  readily  compacted,  while  in  the 
poor  Hanford  and  San  Joaquin  soils  the  pots  receiving  leakage  water 
showed  markedly  better  growth. 

To  minimize  such  errors,  as  much  as  possible,  triplicates  were 
used,  as  above  explained,  besides  repeating  the  series.  In  working 
out  the  final  averages  of  the  crop  it  was  suggested  that  a  selection  be 
made  of  the  crop  dry  weights,  in  case  that  there  was  a  marked  varia- 
tion between  the  triplicates,  using  the  two  weights  close  together,  and 
excluding  the  third  if  it  were  widely  divergent.  However,  when  one 
begins  to  select  certain  figures  from  a  series,  and  bases  comparisons 
upon  these  alone,  there  is  apt  to  be  the  tendency  to  select  those  figures 
that  will  prove  the  point  in  question,  unless  there  is  some  known  dis- 
turbing factor  causing  the  divergence  and  which  warrants  the  exclu- 
sion of  certain  figures. 

Other  cases  that  are  rather  hard  to  deal  with  are  those  in  which 
the  number  of  plants  reaching  maturity  was  not  up  to  the  standard  to 
which  the  series  was  thinned  when  the  plants  were  young.  This  fail- 
ure may  have  been  due  to  poor  germination,  or  to  accidental  destruc- 
tion of  the  plants  during  growth.  Sometimes  less  than  the  standard 
number  of  plants  will  give  a  much  greater  dry  weight  per  plant  than 
the  normal  number.  It  was  not  deemed  advisable  to  use  the  weight 
per  plant,  but  rather  to  use  the  total  dry  weight  of  the  crop,  and  only 
consider  of  value  the  series  in  which  the  number  of  plants  per  pot 
was  practically  constant. 

In  the  greenhouse  work  the  Diablo  clay  adobe,  the  Altamont  clay 
loam,  and  the  Hanford  fine  sandy  loam  samples  were  compared  by 


1919] 


Pendleton:  A  Study  of  Soil  Types 


433 


two  croppings,  while  one  crop  was  grown  on  the  San  Joaquin  sandy 
loam  soils.  The  infertility  of  the  San  Joaquin  soils,  in  some  cases 
extreme,  greatly  retarded  crop  growth. 

Diablo  clay  adobe.  First  crop. — Due  to  the  presence  of  wild  oat 
seed  in  all  the  four  samples  of  this  soil,  and  the  inability  to  distin- 
guish the  young  wild  oat  plants  from  the  planted  oats,  wheat,  or 
barley  when  thinning,  the  value  of  the  results  of  the  grain  crops  in 
this  series  is  much  decreased.    The  averages  plotted  include  the  total 


Z5 


20 


*\5 

a 

u 

10 


Oats 
and 

Bur  Clover 
Bur  Clover 


as  col  us 


Soils 

Fig.  27.  Graph  showing  the  total  dry  matter  produced  by  wheat,  barley, 
oats,  Phaseolus,  bur  clover,  and  oats  and  bur  clover  on  the  four  samples  of 
Diablo  clay  adobe.     First  crop. 


crop,  whether  pure  or  with  a  greater  or  less  quantity  of  the  wild  oats, 
though  the  number  of  plants  harvested  was  usually  six  or  less. 
Planting  the  oats  and  bur  clover  together  was  not  a  success.  In  three 
of  the  soils  the  crop  of  bur  clover  alone  was  greater  than  that  of  the 
six  bur  clover  plants  plus  the  six  oat  plants.  Plate  44  shows  how,  in 
some  cases,  the  oats  dominated,  and  in  others  the  bur  clover  was 
superior.  On  the  soils  of  this  type  bur  clover  was  the  most  satisfactory 
crop,  while  the  white  beans  were  the  most  unsatisfactory  of  all. 

Comparing  the  total  crops  (see  fig.  27  and  tables  45-50),  it  will 
be  seen  that  1,  5,  2,  6  is  the  order  for  bur  clover,  soil  no.  1  giving  the 


4 


434 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


best  crop  and  soil  no.  6  the  poorest,  while  nos.  5,  1,  2,  6  is  the  order 
for  barley  and  wheat.  Oats  show  nearly  double  the  crop  on  soil  5 
that  it  does  on  any  of  the  other  three  soils.  There  is  thus  a  general 
agreement  between  the  indicators  that  the  soils  are  not  of  the  same 
productivity. 


Table  45 — Diablo  Clay  Adobe,  First  Crop 
Wheat 
Planted,  November  6,  1915.     Harvested,  July  10,  1916 

Straw  Grain               Total  dry  matter 

, A .  A „     , A . 

r                                  \  f                                  \  r                                  \ 

No.                              Average  Average                    Average 

Pot              plants          Weight        weight  Weight     weight       Weight      weight 

1-1       Wheat  2         3.65  0.25 

Oats      4         2.15  0.69                        6.74 

1-2       Wheat  0 

Oats      6         4.05  2.47                        6.51 

1-3       Wheat  1         1.83 

Oats      5         5.20         5.62  1.64         1.68         8.66         7.30 

2-1       Wheat  5         5.33  0.05 

Oats      1         0.43  i        5.81 

2-2       Wheat  4         3.53  0.03 

Oats      2         0.69  0.04                        4.31 

2-3       Wheat  3         2.55 

Oats      3         1.39         4.63  0.49         0.21         4.43         0.84 


Notes 


5-1 

Wheat  2 

4.33 

Oats      4 

1.56 

5-2 

Wheat  3 

7.28 

Oats      2 

3.23 

5-3 

Wheat  3 

7.09 

Oats      2 

0.64 

6-1 

Wheat  2 

2.19 

Oats      4 

1.03 

6-2 

Wheat  0 

Oats      5 

1.72 

6-3 

Wheat  2 

2.31 

Oats      4 

2.51 

8.04 


0.90 
0.42 
1.81 
1.02 
0.48 
0.47 


7.21 


13.44 


1.70         8.68         9.74 


3.22 


1.72 


3.25         0.70         0.17         5.53         3.49 


1919] 


Pendleton:   A  Study  of  Soil  Types 


435 


Table  46 — Diablo  Clay  Adobe,  First  Crop 
Barley 
Planted,  November  6,  1915.     Harvested,  April  28,  1916 
Straw  Grain  Total  dry  matter 


Pot 

No. 
plants 

r 
Weight 

Average 

weight 

r 
Weight 

Average 
weight 

r 
Weight 

Average 
weight 

1-1 

6 

5.19 

1.06 

6.25 

1-2 

Barley  5 
Oats      1 

4.79 

0.75 

5.54 

1-3 

Barley  4 

5.75 

1.34 

Oats      2 

5.24 

0.98 

1.38 

8.07 

6.62 

2-1 

6 

5.12 

1.05 

6.17 

2-2 

6 

4.87 

1.71 

6.58 

2-3 

Barley  5 

2.78 

0.49 

Oats      1 

0.69 

4.49 

0.23 

1.16 

4.19 

5.65 

5-1 

6 

6.59 

2.12 

8.70 

5-2 

Barley  5 

3.01 

Oats      1 

2.56 

0.25 

3.25 

5-3 

Barley  5 

3.01 

Oats      1 

8.43 

5.86 

0.04 

1.95 

11.48 

7.81 

6-1 

6 

4.62 

1.26 

5.88 

6-2 

6 

4.36 

1.25 

5.61 

6-3 

Barley  5 

0.33 

Oats      1 

3.49 

4.16 

0.24 

1.02 

4.06 

5.18 

Notes 


Table  47 — Diablo  Clay  Adobe,  First  Crop 

Oats 

Planted,  November  6,  1915.     Harvested,  May  8,  1916 

Straw  Grain  Total  dry  matter 


Pot 

No. 
plants 

r 
Weight 

Average 
weight 

r 
Weight 

Average 
weight 

r 
Weight 

Average 
weight 

1-1 

6 

4.11 

1.24 

5.35 

1-2 

6 

6.56 

2.59 

9.15 

1-3 

6 

4.76 

5.14 

1.34 

1.72 

6.10 

6.86 

2-1 

6 

4.36 

1.10 

5.46 

2-2 

6 

total 

only 

total i 

only 

6.92 

2-3 

6 

6.66 

5.51 

2.06 

1.58 

8.72 

7.03 

5-1 

7 

7.55 

2.59 

10.15 

5-2 

6 

10.66 

4.38 

15.04 

5-3 

6 

10.10 

3.12 

13.22 

6-1 

6 

4.70 

1.48 

6.18 

6-2 

6 

6.81 

1.42 

8.22 

6-3 

6 

6.78 

1.09 

7.88 

Notes 


One  barley  plant 


436  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table  48 — Diablo  Clay  Adobe,  First  Crop 

Bur  Clover 

Planted,  November  6,  1915.     Harvested,  May  8,  1916 


No. 
plants 

St 

raw 

Gi 

rain 

Total  dr 

r 

Weight 

y  matter 

Pot 

f 
Weight 

Average 
weight 

r 
Weight 

Average 
weight 

Average 
weight 

1-1 

5 

11.01 

15.13 

26.32 

1-2 

4 

9.07 

14.15 

23.22 

1-3 

6 

12.18 

10.75 

13.02 

14.16 

25.20 

24.91 

2-1 

6 

8.26 

9.89 

18.16 

2-2 

5 

7.45 

8.93 

16.39 

2-3 

6 

7.97 

7.89 

8.02 

8.98 

15.99 

16.84 

5-1 

7 

11.14 

12.33 

23.48 

5-2 

8 

10.67 

13.05 

23.72 

5-3 

7 

10.55 

10.79 

9.76 

11.71 

20.31 

22.50 

6-1 

6 

7.96 

8.73 

16.69 

6-2 

6 

8.26 

9.76 

18.02 

6-3 

6 

6.87 

7.69 

6.04 

8.18 

12.91 

15.87 

Table  49— 

Diablo  Clay  Adobe,  First  Crop 

Notes 


Oats  and  Bur  Clover 
Planted,  November  6,  1915.     Harvested,  May  8,  1916 


No. 
plants 

St 

raw 

Grain 

Total  di 
Weight 

•y  matter 

Pot 

r 

Weight 

Average 
weight 

r 
Weight 

Average 
weight 

Average 
weight 

1-1 

Clover  3 

10.37 

11.93 

22.30 

Oats      6 

2.38 

0.14 

2.52 

1-2 

Clover  6 

8.19 

9.28 

17.47 

Oats      6 

3.48 

0.70 

4.16 

1-3 

Clover  6 

13.53 

9.81 

23.34 

Oats      6 

2.65 

13.53 

0.27 

10.71 

2.92 

24.24 

2-1 

Clover  6 

2.13 

2.57 

4.70 

Oats      6 

5.77 

1.81 

7.58 

2-2 

Clover  6 

4.24 

4.62 

8.87 

Oats      6 

4.56 

1.26 

5.82 

2-3 

Clover  6 

3.43 

4.51 

7.94 

Oats      6 

3.20 

7.75 

0.46 

5.08 

3.66 

12.85 

5-1 

Clover  6 

10.88 

9.78 

20.66 

Oats      6 

2.45 

0.27 

2.71 

5-2 

Clover  5 

10.52 

9.32 

19.84 

Oats      6 

2.19 

0.51 

2.79 

5-3 

Clover  5 

8.31 

8.36 

16.66 

Oats      6 

3.45 

12.60 

0.66 

9.63 

4.10 

22.26 

6-1 

Clover  6 

8.90 

9.56 

18.46 

Oats     6 

3.10 

0.35 

3.45 

6-2 

Clover  6 

9.01 

5.82 

14.83 

Oats      6 

2.09 

0.52 

2.61 

6-3 

Clover  6 

6.51 

10.45 

16.97 

Oats      5 

2.33 

10.65 

0.47 

9.06 

2.80 

19.71 

Notes 


1919]  Pendleton:   A  Study  of  Soil  Types  437 

Table  50 — Diablo  Clay  Adobe,  First  Crop 

Phaseolus  vulgaris 

Planted,  April  4,  1916.     Harvested,  October  7,  1916 

Straw  Grain  Total  dry  matter 


Notes 
Growth  poor  and 
slow  through- 


Pot 

No. 
plants 

Weight 

Average 
weight 

r 

Weight 

Average 
weight 

Weight 

Average 
weight 

1-1 

8 

2.05 

0.58 

2.63 

i 

1-2 

1 

0.94 

0.87 

1.81 

1-3 

12 

2.86 

1.95 

1.37 

0.94 

4.23 

2.89 

2-1 

3 

0.53 

0.21 

0.74 

2-2 

10 

0.83 

0.83 

2-3 

17 

1.26 

0.87 

0.11 

0.10 

1.37 

0.98 

5-1 

3 

0.53 

0.40 

0.93 

5-2 

2 

0.46 

0.41 

0.87 

5-3 

0.33 

0.27 

0.60 

6-1 

2 

0.22 

0.22 

6-2 

6-3 

1 

0.23 

0.15 

0.23 

0.15 

Diablo  clay  adobe.  Second  crop. — The.  crops  used  in  this  plant- 
ing were  milo  (two  series,  one  following  oats  and  bur  clover,  and  the 
other  following  oats  alone),  cowpeas,  millet,  and  soy  beans.  The 
crop  was  thinned  as  follows :  milo  to  eight  plants,  millet  to  twelve, 
soy  beans  to  six,  and  cowpeas  to  six.  The  total  dry  weight  (tables 
51-55)  of  the  largest  leguminous  crop  in  this  planting  is  about  one- 
third  of  that  of  the  bur  clover  in  the  first  planting ;  though  the  grains 
are  proportionately  not  nearly  so  much  less  than  in  the  first  crop. 
Soil  no.  2  has  the  least  pronounced  adobe  structure,  but  was  the  most 
easily  puddled.  The  plants  in  one  of  the  pots  of  soy  beans  of  soil 
no.  2  were  entirely  killed  by  too  much  water. 

Comparing  the  relative  growth  on  the  soils,  the  notes  made  while 
the  crops  were  growing  coincide  very  closely  with  the  dry  weights. 
As  to  the  relative  crop  production  (fig.  28),  it  can  be  said  that  soils 
nos.  1  and  5  produced  larger  crops  than  soils  nos.  2  and  6.  Thus  the 
second  crop  results  substantiate  those  of  the  first  crop. 


438 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


So.y  Beans 

j-Milo  B 


•~*"f'!~.?M<r'Cow  Peas 

Millet 
5  6 

Soils 

Pig.  28.  Graph  showing  the  total  dry  matter  produced  by  milo  (two 
series),  millet,  soy  beans,  and  cowpeas  on  the  four  samples  of  Diablo  clay 
adobe.     Second  crop. 


Wheat 
Oats  +  Bur  CI  over 
Barley 
Oats 

Bur  Clover 
Phaseolas 


Fig.  29.  Graph  showing  the' total  dry  matter  produced  by  wheat,  barley, 
oats,  bur  clover,  Phaseolus,  and  oats  and  bur  clover  on  the  three  samples  of 
Altamont  clay  loam.     First  crop. 


Soy  Beans  B 
5qy  Beans  A 
Cow  Peas  A 
Cow  Peas  B 

Milo  A 
M.loB 


Fig.  30.  Graph  showing  the  total  dry  matter  produced  by  milo  (two  series), 
cowpeas  (two  series),  and  soy  beans  (two  series)  on  the  three  samples  of 
Altamont  clay  loam.     Second  crop. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


439 


Pot 

No. 
plants 

1-1 

8 

1-2 

8 

1-3 

7 

2-1 

8 

2-2 

8 

2-3 

8 

5-1 

8 

5-2 

6 

5-3 

7 

6-1 

9 

6-2 

8 

6-3 

8 

Table  51 — Diablo  Clay  Adobe,  Second  Crop 

Milo  A  (following  oats) 

Planted,  June  3,  1916.     Harvested,  November  16,  1916 

Straw  Grain               Total  dry  matter 

A . A .     . A . 

r                                \  r                                \  r                                \ 

Average  Average                     Average 

Weight        weight  Weight       weight     Weight       weight                    Notes 

4.87  4.87  Excluded  from 

10.00  10.00  average 

4.50         4.68  4.50         4.68 

2.59  2.59 

3.73  3.73 

2.92         3.08  2.92         3.08 

4.03  4.03 

5.13  5.13 

8.44  8.44 

3.49  3.49 

3.08  3.08 

2.98         3.18  2.98         3.18 


Pot 

No. 

plants 

1-1 

8 

1-2 

8 

1-3 

8 

2-1 

8 

2-2 

8 

2-3 

8 

5-1 

8 

5-2 

8 

5-3 

8 

6-1 

8 

6-2 

8 

6-3 

8 

Table  52 — Diablo  Clay  Adobe,  Second  Crop 

Milo  B  (following  oats  and  bur  clover) 

Planted,  June  3,  1916.     Harvested,  November  16,  1916 

Straw  Grain               Total  dry  matter 

. A „         . A „    , A „ 

r                             \  (                              \  r                              \ 

Average  Average                     Average 

Weight        weight  Weight       weight     Weight       weight 

6.41  .  6.41 

8.78  8.78 

6.21         7.14  6.21         7.14 

3.92  3.92 

4.52  4.52 

3.63         4.02  3.63         4.02 

10.34  10.34 

6.17  6.17 

5.20         7.24  5.20         7.24 

9.29  9.29 

3.70  3.70 

4.09         5.69  4.09         5.69 


Notes 


440  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

Table  53 — Diablo  Clay  Adobe,  Second  Crop 

Millet  (following  bur  clover) 

Planted,  June  3,  1916.     Harvested,  October  6,  1917 


Notes 


No. 
plants 

Straw 

Gi 

rain 

Total  dry 

r 

Weight 

matter 

Pot 

r    ' 
Weight 

Average 
weight 

r 
Weight 

Average 
weight 

Average 
weight 

1-1 

12 

1.52 

1.44 

2.96 

1-2 

11 

1.34 

0.90 

2.24 

1-3 

11 

2.03 

1.63 

1.15 

1.16 

3.18 

2.79 

2-1 

12 

1.26 

1.29 

2.55 

2-2 

11 

1.49 

1.32 

2.80 

2-3 

12 

0.93 

1.23 

0.88 

1.16 

1.80 

2.39 

5-1 

10 

2.26 

2.19 

4.45 

5-2 

12 

3.35 

3.36 

6.71 

5-3 

12 

2.02 

2.54 

1.51 

2.35 

3.53 

4.90 

6-1 

11 

1.19 

0.99 

2.18 

6-2 

12 

1.59 

1.23 

2.82 

6-3 

13 

1.26 

1.35 

1.04 

1.09 

2.29 

2.43 

Table  54 — Diablo  Clay  Adobe,  Second  Crop 

Cowpeas  (following  wheat) 

Planted,  August  10,  1916.     Harvested,  November  16,  1916 

Straw  Grain  Total  dry  matter 

, A .  . A „    A 

f  \  i  ^  r  \ 

No.  Average  Average  Average 

Pot  plants       Weight        weight  Weight       weight     Weight       weight  Notes 

1-1  7  2.66  2.66 

1-2  7  5.30  5.30 

1-3  7  3.73         3.89  3.73         3.89 

2-1  6  2.57  2.57 

2-2  6  4.24  4.24 

2-3  6  2.86         3.22  2.86         3.22 

5-1  6  2.74  2.74 

5-2  6  4.30  4.30 

5-3  6  3.64         3.56  3.64         3.56 

6-1  6  3.28  3.28 

6-2  7  4.10  4.10 

6-3  6  3.41         3.60  3.41         3.60 


1919] 


Pendleton :   A  Study  of  Soil  Types 


441 


Table  55 — Diablo  Clay  Adobe,  Second  Crop 

Soy  Beans  (following  barley) 

Planted,  June  6,  1916.     Harvested,  November  14,  1916 


No. 
plants 

Straw 

A 

Gi 

rain 

A 

Total  dry  matter 

A 

f                                 \ 

Average 

Weight       weight 

Pot 

r 

Weight 

> 
Average 
weight 

r 
Weight 

Average 
weight 

Notes 

1-1 

6 

8.48 

0.29 

8.77 

1-2 

6 

8.58 

0.06 

8.64 

1-3 

6 

6.87 

7.98 

0.41 

0.25 

7.28 

8.23 

2-1 

6 

2.12 

2.12 

Excluded  from 

2-2 

4 

3.62 

0.40 

4.02 

average 

2-3 

5 

6.07 

4.84 

0.38 

0.39 

6.45 

5.23 

5-1 

6 

5.84 

0.16 

6.00 

5-2 

6 

7.96 

0.64 

8.60 

5-3 

6 

6.47 

6.76 

0.69 

0.49 

7.16 

7.25 

6-1 

6 

7.61 

0.24 

7.85 

6-2 

6 

7.99 

0.45 

8.43 

6-3 

6 

7.26 

7.62 

0.17 

0.28 

7.43 

7.90 

Altamont  clay  loam.  First  crop. — The  crops  planted  in  this  soil 
were  wheat,  barley,  oats,  bur  clover,  Phaseolus,  and  oats  and  bur 
clover  together.  The  standard  number  to  which  the  plants  were 
thinned  was  six,  except  in  the  oats  and  bur  clover  series,  where  three 
plants  of  each  were  allowed  to  remain. 

With  regard  to  the  comparative  crop  producing  power  of  these 
soils  under  these  conditions,  soil  no.  4  is  the  best,  with  soil  no.  3  as 
the  second,  and  soil  no.  7  was  the  poorest  (tables  56-60,  fig.  29).  The 
dry  weight  data  decidedly  corroborate  the  impression  given  by  the 
greenhouse  appearance  of  the  crops.  However,  as  all  the  crops  were 
so  small  on  all  the  series,  the  figures  do  not  show  as  much  as  they 
might  have  shown  had  the  growth  been  more  nearly  optimum  for  the 
several  crops. 

Table  56 — Altamont  Clay  Loam,  First  Crop 

Wheat 

Planted,  February  25,  1916.    Harvested,  July  10,  1916 


Notes 


No. 
plants 

Straw 

A 

Grain 

A 

Total  dr 
Weight 

y  matter 

A 

Pot 

Weight 

Average 
weight 

Weight 

Average 
weight 

Average 
weight 

3-1 

6 

2.62 

1.23 

3.85 

3-2 

6 

2.93 

1.09 

3.92 

3-3 

6 

2.86 

2.80 

1.04 

1.12 

3.91 

3.92 

4-1 

6 

4.20 

1.78 

5.97 

4-2 

6 

4.03 

1.22 

5.25 

4-3 

6 

6.20 

4.81 

1.13 

1.38 

7.34 

6.19 

7-1 

6 

2.64 

1.11 

3.76 

7-2 

6 

2.58 

0.99 

3.64 

7-3 

6 

2.90 

2.71 

0.71 

0.93 

3.61 

3.64 

442 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table  57 — Altamont  Clay  Loam,  First  Crop 

Barley 

Planted,  April  4,  1916.     Harvested,  July  11,  1916 


No. 
plants 

St 

raw 

Grain 

Total  dr 

r 

Weight 

y  matter 

Pot 

f 
Weight 

Average 
weight 

Weight 

Average 
weight 

Average 
weight 

3-1 

1.10 

0.76 

1.86 

3-2 

1.45 

1.40 

2.85 

3-3 

1.39 

1.31 

1.18 

1.11 

2.57 

2.43 

4-1 

1.99 

1.43 

3.42 

4-2 

1.90 

1.57 

3.47 

4-3 

2.39 

2.09 

1.85 

1.62 

4.25 

3.71 

7-1 

0.98 

0.90 

1.88 

7-3 

1.06 

1.00 

0.59 

0.71 

1.64 

1.71 

Notes 


Table  58 — Altamont  Clay  Loam,  First  Crop 

Oats 

Planted,  February  25,  1916.     Harvested  July  11,  1916 


No. 

plants 

6 

SI 

raw 

A 

Grain 

Total  dry  matter 

Pot 
3-1 

r 
Weight 

1.36 

Average 
weight 

r 

Weight 
0.38 

Average 
weight 

Weight 
1.74 

Average 
weight 

3-2 

6 

1.60 

0.67 

2.27 

3-3 

6 

1.70 

1.55 

0.47 

0.51 

2.17 

2.06 

4-1 

6 

3.05 

1.42 

4.47 

4-2 

4 

2.62 

1.13 

3.76 

4-3 

4 

3.46 

3.04 

1.81 

1.45 

5.27 

4.50 

7-1 

6 

1.21 

0.29 

1.51 

7-2 

6 

1.00 

0.42 

1.42 

7-3 

6 

0.88 

1.03 

0.35 

0.35 

1.23 

1.38 

Notes 


Table  58 — Altamont  Clay  Loam,  First  Crop 

Bur  Clover 

Planted,  February  25,  1916.     Harvested,  July  8,  1916 


No. 
plants 

6 

Straw 

A 

Gi 

*ain 

Total  dr 

r 

Weight 
2.53 

y  matter 

Pot 
3-1 

r 

Weight 
1.50 

Average 
weight 

Weight 
1.03 

Average 
weight 

Average 
weight 

3-2 

6 

0.88 

1.17 

2.18 

3-3 

6 

0.63 

1.00 

1.34 

1.18 

1.96 

2.18 

4-1 

6 

2.48 

1.47 

3.95 

4-2 

6 

2.57 

1.57 

4.14 

4-3 

4 

2.50 

2.52 

1.31 

1.45 

3.81 

3.97 

7-1 

6 

0.47 

0.66 

1.13 

7-2 

6 

0.53 

0.24 

0.78 

7-3 

6 

0.37 

0.46 

0.20 

0.36 

0.57 

0.82 

Notes 


1919] 


Pendleton:   A  Study  of  Soil  Types 


443 


Table  59 — Altamont  Clay  Loam,  First  Crop 
Oats  and  Bur  Clover 


Planted, 

April  14, 

1916. 

Harvested,  July  8,  191 

No. 
plants 

Straw 

A 

Grain 

A 

Total  di 

height 

•y  matter 

K 

Pot 

r 

Weight 

"\      r 
Average 
weight       Weight 

>  r 

Average 

weight     V\ 

Average 
weight 

3-1 

B.C. 

3 

0.98 

1.25 

2.23 

Oats 

3 

0.77 

0.10 

0.88 

3-2 

B.C. 

4 

0.79 

1.17 

1.96 

Oats 

4 

0.68 

0.22 

0.90 

3-3 

B.C. 

4 

0.48 

0.91 

1.38 

Oats 

4 

0.78 

1.49 

0.30 

1.32 

1.07 

2.81 

4-1 

B.C. 

3 

0.67 

0.32 

0.99 

Oats 

3 

2.42 

1.75 

4.17 

4-2 

B.C. 

3 

0.40 

0.62 

1.01 

Oats 

3 

2.63 

1.38 

4.01 

4-3 

B.C. 

3 

0.51 

0.21 

0.72 

Oats 

3 

2.77 

3.14 

1.09 

1.78 

3.86 

4.92 

7-1 

B.C. 

3 

0.20 

0.27 

0.47 

Oats 

3 

0.86 

0.74 

1.60 

7-2 

B.C. 

3 

0.28 

0.22 

0.50 

Oats 

3 

1.27 

0.95 

2.22 

7-3 

B.C. 

4 

0.42 

0.37 

0.74 

Oats 

2 

0.64 

1.22 

0.44 

0.98 

1.08 

2.20 

Notes 


Table  60 — Altamont  Clay  Loam,  First  Crop 

Beans  (Phaseolus) 

Planted,  February  25,  1916.     Harvested,  July  11,  1916 


No. 
plants 

Straw 

A 

Grain 

Total  dr; 
Weight 

y  matter 

Pot 

Weight 

Average 
weight 

r 

Weight 

Average 
weight 

Average 
weight 

3-1 

6 

2.82 

0.13 

2.96 

3-2 

6 

1.24 

0.35 

1.59 

3-3 

6 

1.32 

1.79 

0.32 

0.27 

1.64 

2.06 

4-1 

5 

1.71 

0.25 

1.96 

4-2 

6 

1.41 

0.59 

2.01 

4-2 

6 

1.81 

1.64 

0.59 

0.48 

2.41 

2.12 

7-1 

1 

0.11 

0.09 

0.20 

7-2 

6 

0.53 

0.53 

7-3 

5 

0.63 

0.43 

0.03 

0.63 

0.46 

Notes 


Altamont  clay  loam.  Second  crop. — A  slightly  different  scheme 
was  used  in  the  planting  of  this  series,  only  three  crops  were  used, 
i.e.,  soy  beans,  cowpeas,  and  milo.  Two  sets  of  pots  were  planted  to 
each  crop,  one  of  the  two  sets  having  previously  been  planted  to  a 
legume,  and  the  other  to  a  non-legume.    The  milo  was  thinned  so  that 


444  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

one  pot  of  each  triplicate  set  would  have  8  plants,  the  second  of  the 
set  12  plants,  and  the  last  16  plants.  It  was  found  that  the  wide 
variation  in  the  number  of  plants  had  but  little  effect  upon  the  dry 
weight  produced  per  pot  (tables  61-66).  The  effect  was  indeed  so 
slight  that  the  totals  were  averaged  up  as  usual.  Figure  30  shows 
distinctly  that  there  was  very  little  variation  as  regards  total  produc- 
tion among  these  soils,  so  little  as  not  to  warrant  any  conclusions  as 
regards  substantiation  of,  or  disagreement  with,  the  first  crop.  It 
will  be  noticed  in  the  second  crop  of  the  Diablo  series,  as  well  as  in 
that  of  the  Altamont  series,  that  the  maintenance  of  the  soils  under 
the  same  conditions  for  a  year  or  more  seems  to  bring  them  quite 
rapidly  to  an  average  crop  producing  power. 

Table  61 — Altamont  Clay  Loam,  Second  Crop 

Milo  A   (following  wheat) 

Planted,  August  10,  1916.     Harvested,  November  17,  1916 

Straw  Grain  Total  dry  matter 

No.  Average  Average  Average 

Pot  plants      Weight        weight      Weight      weight     Weight      weight  Notes 

3-1  8  0.77  0.77 

3-2  12  1.01  1.01 

3-3  16  0.97         0.92  0.97         0.92 

4-1  8  1.22  1.22 

4-2  12  2.32  2.32 

4-3  16  2.08         1.87  2.08         1.87 

7-1  8  0.59  0.59 

7-2  12  0.99  1.29 

7-3  16  1.29         0.95  1.29         0.95 


Table  62 — Altamont  Clay  Loam,  Second  Crop 

Milo  B 

Planted,  August  10,  1916.     Harvested,  November  15,  1916 

Straw  Grain  Total  dry  matter 

. A .         . A .     , A . 

t  ^      r  ^>  f  \ 

Average  Average  Average 

Weight        weight      Weight      weight     Weight      weight  Notes 

0.82  0.82 

1.13  1.13 

1.15         1.03  1.15         1.03 

1.28  1.28 

1.82  1.82 

1.45         1.52  1.45         1.52 

0.66  0.66 

0.96  0.96 

0.02         0.85  0.92         0.85 


Pot 

No. 
plants 

3-1 

8 

3-2 

12 

3-3 

16 

4-1 

8 

4-2 

12 

4-3 

16 

7-1 

8 

7-2 

12 

7-3 

10 

1919] 


Pendleton:   A  Study  of  Soil  Types 


445 


Table  63 — Altamont  Clay  Loam,  Second  Crop 

Cowpeas  A  (following  barley) 

Planted,  August  10,  1916.     Harvested,  November  17,  1916 


Straw 


Pot 

No. 

plants 

r 

Weight 

Average 
weight 

3-1 

6 

3.48 

3-2 

6 

4.50 

3-3 

6 

3.00 

3.66 

4-1 

6 

2.44 

4-2 

6 

2.59 

4-3 

6 

3.40 

2.81 

7-1 

6 

2.64 

7-2 

6 

1.93 

7-3 

6 

2.15 

2.24 

Grain 

A 


Average 
Weight       weight 


Total  dry  matter 

Weight 

Average 
weight 

3.48 

4.50 

3.00 

3.66 

2.44 

2.59 

3.40 

2.81 

2.64 

1.93 

2.15 

2.24 

Notes 


Table  64 — Altamont  Clay  Loam,  Second  Crop 

Cowpeas  B  (following  oats  and  bur  clover) 

Planted,  August  10,  1916.     Harvested,  November  14,  1916 

Straw  Grain  Total  dry  matter 


Pot 

No. 
plants 

Weight 

Average 
weight 

Average 
Weight       weight 

r 
Weight 

Average 
weight 

3-1 

6 

4.16 

4.16 

3-2 

6 

3.63 

3.63 

3-2 

6 

2.77 

3.52 

2.77 

3.52 

4-1 

6 

3.35 

3.35 

4-2 

6 

2.70 

2.70 

4-3 

6 

1.94 

2.66 

1.94 

2.66 

7-1 

6 

1.51 

1.51 

7-2 

6 

2.10 

2.10 

7-3 

6 

2.85 

2.15 

2.85 

2.15 

Notes 


Table  65 — Altamont  Clay  Loam,  Second  Crop 

Soy  Beans  A  (following  oats) 

Planted,  August  10,  1916.     Harvested,  November  17,  1916 

Straw  Grain  Total  drv  matter 

, A . A . A . 

t  "\        t  \  t  \ 

No.  Average  Average  Average 

Pot  plants       Weight        weight       Weight       weight     Weight       weight 

3-1  6  4.85 4.85 

3-2  6  4.25  4.25 

3-3  6  4.50         4.53  4.50         4.53 

4-1  6  3.53  3.53 

4-2  6  3.59  3.59 

4-3  6  4.88         4.00  4.88         4.00 

7-1  6  3.42  3.42 

7-2  6  3.34  3.34 

7-3  6  3.42         3.39  3.42         3.39 


Notes 


446  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

Table  66 — Altamont  Clay  Loam,  Second  Crop 

Soy  Beans  (following  Phaseolus) 

Planted,  August  10,  1916.     Harvested  November  17,  1916 

Straw  Grain  Total  dry  matter 

.  . A .          . A .     . A „ 

r  \     f  \  r  \ 

No.  Average  Average  Average 

Pot  plants       Weight        weight       Weight       weight     Weight       weight  Notes 

3-1  6  5.64  5.64 

3-2  6  4.94  4.94 

3-3  6  4.84         5.14  4.84         5.14 

4-1  6  4.74  4.74 

4-2  6  4.64  4.64 

4-3  6  4.71         4.70  4.71         4.70 

7-1  6  5.25  5.25 

7-2  6  3.28  3.28 

7-3  6  4.39         4.31  4.39         4.31 


Hanford  fine  sandy  loam.  First  crop. — This  soil  type,  with  sam- 
ples from  nine  different  localities  in  California,  gave  a  much  wider 
range  of  conditions  and  made  a  much  more  interesting  series.  The 
plants  used  as  indicators  in  this  series  were  milo  (twice),  millet,  cow- 
peas  (twice),  and  soy  beans.  The  milo  was  thinned  to  eight  plants 
per  pot,  the  millet  to  twelve  plants,  and  the  cowpeas  and  soy  beans 
to  six  plants.  Set  A  of  cowpeas,  and  set  B  of  milo  were  unfavorably 
located,  so  that  the  results  of  these  sets  should  be  discounted. 

It  is  interesting  to  note  the  large  differences  in  the  average 
weights  from  soil  to  soil  (tables  67-72,  and  fig.  31),  as  compared  with 
the  photographs,  in  which  little  variation  appears.  See  especially  the 
soy  bean  series.    In  this  series  two  things  are  to  be  noted : 

1.  Averages  on  soils  nos.  15  and  25  are  hardly  representative  be- 
cause in  both  cases  excess  moisture,  from  a  leaky  roof  and  too  heavy 
watering,  depressed  growth.  The  tendency  to  become  compact  and  to 
remain  wet  and  cold  shown  by  soil  no.  15  aided  the  milo  and  depressed 
the  soy  beans. 

2.  The  loose,  open  texture  of  soil  no.  22  seemingly  favored  the  soy 
bean  growth,  though  the  other  plants  did  not  do  as  well  on  this  soil 
as  on  most  of  the  others. 


1919] 


Pendleton:   A  Study  of  Soil  Types 


447 


Comparing  the  more  satisfactory  grains,  milo  A  and  millet,  it  will 
be  seen  that  there  is  somewhat  of  a  parallelism  from  soil  to  soil.  The 
legumes  do  not  always  respond  similarly  to  the  grains,  as  in  the  Diablo 
first  crop,  yet  in  the  Diablo  second  crop  and  the  Altamont  first  and 
second  crops  the  response  of  grain  and  legume  seems  quite  similar. 
Hence,  it  is  not  safe  in  every  case  to  judge  as  to  the  relationships 
shown  by  legumes  and  non-legumes. 


SqyB^o/* 


Fig.  31 

Fig.  31.  Graph  showing  the  total  dry  matter  produced  by  millet,  milo  (two 
series),  cowpeas  (two  series),  and  soy  beans  on  the  nine  samples  of  Hanford 
fine  sandy  loam.     First  crop. 


Considering  all  the  variations,  one  might  say  that  soil  no.  23  was 
seemingly  among  the  better  soils,  and  soils  nos.  16  and  22  among  the 
poorer  soils.  Yet  when  discussing  whether  the  soils  be  the  same  or 
similar,  according  to  the  criterion  of  the  dry  weight,  one  of  the  Han- 
ford groups  will  be  similar  according  to  one  crop,  and  an  overlapping 
group  similar  according  to  the  second  crop.  It  can  be  said  with  rea- 
sonable certainty  that  these  Hanford  soils  are  not  closely  similar  to 
one  another. 


448 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Pot 
14-1 
14-2 
14-3 


15-1 
15-2 
15-3 

16-1 
16-2 
16-3 

19-1 
19-2 
19-3 

20-1 
20-2 
20-3 

22-1 
22-2 
22-3 

23-1 
23-2 
23-3 

24-1 
24-2 
24-3 

25-1 
25-1 
25-2 
25-3 


No. 

plants 


Table  67 — Hanford  Fine  Sandy  Loam,  First  Crop 

Milo  A 

Planted,  June  10,  1916.     Harvested,  November  18,  1916 

Straw  Grain  Total  dry  matter 

„ A A .    . A 

(  \     r  \  r  \ 

Average  Average  Average 

Weight      weight       Weight      weight     Weight     weight  Notes 

15.34  15.34  Most  plants  bore 

12.50  12.50  no  grain;  some 

10.15       12.66  10.15       12.66  ^rain    was    im- 

mature  at  har- 
vest. These 
cases  noted, 
but  no  grain 
weighed. 

13.14  13.14 

14.50  14.50 

15.21       14.28  15.21       14.28    Not  mature 

8.67  8.67 

5.86  5.86 

4.76         6.43  4.76         6.43 

7.65  7.65 

14.11  14.11 

7.01  7.01 

14.10  14.10 

10.15  10.15 

7.68  10.64  7.68       10.64    Not  mature 

5.34  5.34 

5.88  5.88 

5.35  5.52  5.35         5.52 

8.90  8.90  Not  mature 

10.04  10.04  Not  mature 

8.67         9.20  8.67         9.20 

10.82  10.82 

9.92  9.92  Not  mature 

6.01         8.92  6.01         8.92     Not  mature 

11.26  11.26 

11.26  11.26 

5.70  5.70 

9.33  8.76  9.33         8.76 


1919]  Pendleton:   A  Study  of  Soil  Types  449 


Table  68 — Hanford  Fine  Sandy  Loam,  First  Crop 

Milo  B 

Planted,  June  10,  1916.     Harvested,  November  20,  1916 

Straw  Grain  Total  dry  matter 

A A. A 

No.  Average  Average                     Average 

Pot        plants  Weight  weight        Weight       weight  Weight     weight                     Notes 

14-.,           8  10.75  10.75 

14-2           8  10.95  10.95 

14-3           8  8.84  10.18           8.84       10.18 

15-1           5  5.25  5.25 

15-2           4  4.62  4.62 

15-3           2  3.92  4.60          3.92         4.60 

16-1           7  7.36  7.36 

16-2           2  2.18  2.18 

16-3           4  2.74  4.09           2.74         4.09 

19-1           3  3.73  3.73 

19-2           8  4.79  4.79 

19-3           8  9.60  6.04          9.60         6.04 

20-1           8  8.14  8.14 

20-2           8  3.23  3.23 

20-3           8  3.22  4.86          3.22         4.86 

22-1           6  4.74  4.74 

22-2          5  3.01  3.01 

22-3           7  3.19  3.64          3.19         3.64 

23-1           8  5.68  5.68 

23-2           5  7.72  7.72 

23-3           8  6.93  6.78          6.93         6.78 

24-1           3  3.16  3.16 

24-2           6  5.64  5.64 

24-3           6  3.26  4.02          3.26         4.02 

25-1          4  3.07  3.07 

25-2          3  2.34  2.34 

25-3           8  4.34  3.25          4.34         3.25 


450  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table  69 — Hanford  Fine  Sandy  Loam,  First  Crop 
Millet 

Planted,  June  10,  1916.     Harvested:   Nos.  15-25,  September  20,  1916;   No.   14, 

October  6,  1916 


No. 
plants 

Straw 

A 

Grain 

Total  dry  matter 

A 

Average 
Weight     weight 

Pot 

r 

Weight 

Average 
weight 

r 
Weight 

Average 
weight 

Notes 

14-1 

12 

3.75 

2.90 

6.65 

14-2 

13 

4.23 

2.95 

7.18 

14-3 

14 

3.46 

3.81 

2.01 

2.62 

5.47 

6.43 

15-1 

12 

3.63 

1.02 

4.65 

15-2 

12 

4.63 

1.31 

5.93 

15-3 

12 

3.86 

4.04 

1.12 

1.15 

4.98 

5.19 

16-1 

13 

1.96 

0.74 

2.70 

16-2 

12 

3.10 

1.81 

4.91 

16-3 

12 

1.52 

2.19 

0.73 

1.09 

2.25 

3.29 

19-1 

12 

1.85 

0.73 

2.58 

Seed  immature 

19-2 

12 

1.71 

0.76 

2.48 

Poor.      Lack    of 

19-3 

12 

2.00 

1.85 

0.69 

0.73 

2.69 

2.58 

drainage? 

20-1 

12 

6.54 

2.78 

9.32 

Possible  error  in 

20-2 
20-3 

12 
12 

1.70 
6.57 

6.55 

1.01 
2.21 

2.50 

2.71 

8.78 

9.05 

grain    weight. 
Original  shows 
6  grams 

22-1 

12 

2.04 

0.65 

2.69 

22-2 

12 

2.32 

0.68 

3.00 

22-3 

12 

4.44 

2.93 

1.90 

1.08 

6.34 

4.01 

23-1 

12 

6.12 

1.21 

7.33 

23-2 

12 

6.13 

2.14 

8.27 

23-3 

12 

6.01 

6.08 

1.97 

1.78 

7.99 

7.86 

24-1 

12 

4.18 

1.50 

5.69 

24-2 

12 

2.80 

0.91 

3.70 

24-3 

11 

4.89 

3.96 

2.08 

1.50 

6.98 

5.46 

25-1 

12 

2.06 

0.77 

2.83 

25-2 

12 

2.01 

0.51 

2.52 

25-3 

12 

4.31 

2.79 

2.15 

1.14 

6.46 

3.94 

1919J 


Pendleton:   A  Study  of  Soil  Types 


451 


Table  70 — Hanford  Fine  Sandy  Loam,  First  Crop 

Soy  Beans 

Planted,  June  10,  1916.     Harvested,  December  11,  1916 

Straw  Beans  Total  dry  matter 

f  ^        f                                                     ^   f  A  ^ 

No.  Average                        Average  Average 

Pot       plants     Weight  weight       Weight      weight  Weight  weight                    Notes 

14-1         6         16.69  16.69  Immature  seed 

14-2         6         16.28  16.28  Immature  seed 

14-3          6         11.89  14.95         0.44         0.15  12.33  15.10     Immature  seed 

15-1          6         14.08  0.23  14.31  Immature  seed 

15-2         6           5.17  5.17  Immature  seed 

15-3         6           6.53  8.59           0.08  6.53  8.67     Immature  seed 

16-1          6         12.63  0.32  12.95  Immature  seed 

16-2         6         14.60  14.60  Immature  seed 

16-3          6         16.60  14.61          0.11  16.60  14.72     Immature  seed 

19-1         6         12.84  12.84  Immature  seed 

19-2         6         11.68  11.68  Immature  seed 

19-3         6         16.03  13.52          16.03  13.52     Immature  seed 

20-1          6           8.77  8.77  Immature  seed 

20-2         6         16.33  16.33  Immature  seed 

20-3         6         14.27  13.13          14.27  13.13     Immature  seed 

22-1          6         20.28  20.28  Immature  seed 

22-2         6         19.44  19.44  Immature  seed 

22-3         6         15.60  18.44          15.60  18.44     Immature  seed 

23-1         6         21.42  21.42  No  seed 

23-2         6         20.75  ......  20.75  No  seed 

23-3         6         20.68  20.95          20.68  20.95     Immature  seed 

24-1          6         17.37  17.37  Immature  seed 

24-2         6         21.24  21.24  Immature  seed 

24-3          6         13.70  17.43          13.70  17.43     Immature  seed 

25-1         6           5.53  .  5.53  Eained  on;  exclud- 
ed from  average 

25-2         6         17.85  17.85  No  seed 

25-3          6         21.58  19.71          21.58  19.71     Immature  seed 


452  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table  71 — Hanford  Fine  Sandy  Loam,  First  Crop 

Cowpeas  A 

Planted,  June  10,  1916.     Harvested,  October  21,  1916 


No. 
plants 

Straw- 

Beans 

A 

Total  d 
f 

Weight 

ry  matter 

Pot 

Average 
Weight       weight 

r                                 ^ 
Average 
Weight       weight 

Average 
weight                    Notes 

14-1 

6 

2.99 

0.93 

3.92 

14-2 

6 

3.52 

3.52 

14-3 

6 

4.18         3.56 

4.18 

3.87 

15-1 

„ 

15-2 

15-3 

-- 

16-1 

1 

2.98 

2.98 

Immature  seed 

16-2 

3 

3.05 

1.50 

4.58 

16-3 

4 

2.60         2.88 

2.16         1.22 

4.76 

4.10 

19-1 

6 

1.49 

0.27 

1.77 

19-2 

6 

1.54 

0.28 

1.82 

19-3 

2 

1.10         1.38 

0.47         0.34 

1.57 

1.72 

20-1 

6 

2.86 

0.32 

3.18 

20-2 

6 

2.08 

0.58 

2.66 

20-3 

6 

2.99         2.64 

0.33         0.41 

3.32 

3.05 

22-1 

5 

1.80 

0.23 

2.02 

22-2 

.. 

22-3 

2 

1.96         1.88 

0.39         0.31 

2.35 

2.19 

23-1 

.. 

23-2 

1 

1.80 

0.76 

2.57 

23-3 

1.80 

0.76 

2.57 

24-1 

2 

1.06 

0.25 

1.30 

24-2 

1 

1.80 

1.29 

3.09 

24-3 

2 

1.75         1.54 

0.45         0.66 

2.20 

2.20 

25-1 

3 

2.74 

2.03 

4.78 

25-2 

1 

1.88 

2.28 

4.17 

25-3 

2 

2.12         2.25 

1.24         1.85 

3.36 

4.10 

1919]  Pendleton:   A  Study  of  Soil  Types                                     453 

Table  72 — Hanford  Fine  Sandy  Loam,  First  Crop 

Cowpeas  B 

Planted,  June  10,  1916.     Harvested,  November  21,  1916 

Straw  Beans  Total  dry  matter 

' \ »     ' * »' " > 

No.  Average  Average  Average 

Pot        plants  Weight  weight        "Weight       weight  Weight     weight                     Notes 

14-1           6  3.94  3.94 

14-2           6  5.93  5.92 

14-3           6  3.32  4.39          3.32         4.39 

15-1           6  7.24  7.24 

15-2           6  5.34  5.34 

15-3           6  4.61  5.74          4.61         5.74 

16-1           6  5.90  5.90 

16-2           6  5.82  5.82 

16-3           6  3.65  5.12          3.65         5.12 

19-1           6  3.34  3.34 

19-2           6  3.38  3.38 

19-3           6  3.87  3.53          3.87         3.53     1  died  early 

20-1           6  3.09  3.09 

20-2           6  3.15  3.15                    1  died  early 

20-3           6  2.80  3.01          ..,. 2.80         3.01 

22-1           6  3.12  3.12 

22-2           6  3.61  3.61 

22-3           6  4.92  3.88 4.92         3.88 

23-1           6  4.59  4.59 

23-2           6  6.04  6.04 

23-3           6  4.08  4.90 4.08         4.90 

24-1           6  3.81  3.81 

24-2           5  4.28  4.28 

24-3           6  6.42  4.84          6.42         4.84 

25-1           5  4.17  4.17 

25-2           6  3.93  3.93                    1  died  early 

25-3           6  4.86  4.32          4.86         4.32 


Hanford  fine  sandy  loam.  Second  crop. — Barley  (twice),  oats, 
wheat,  bur  clover  (Medicago  sp.),  and  Melilotus  indica  were  the  indi- 
cator crops  used  when  the  Hanford  soils  were  planted  the  second  time. 
In  all  cases  a  sufficient  quantity  of  seed  was  used  to  insure  the  growth 
of  more  plants  than  would  be  raised  to  maturity.  Later  the  plants 
in  each  pot  were  thinned  to  six  in  number,  good  specimens  and  well 


454  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

spaced.  The  final  number  of  plants  varied,  but  was  almost  always  six. 
An  attempt  was  made  to  reduce  at  least  partially  the  shading  and 
exposure  effects.  The  pots  were  periodically  changed  from  position 
to  position  on  the  bench. 

The  total  dry  weights  produced  on  the  several  soils  are  interesting 
(tables  73-78,  and  fig.  33).  The  grains  gave  more  uniform  results  in 
this  crop  than  in  the  first.  Soils  nos.  14  and  23  show  the  best  crops, 
and  they  are  the  ones  that  have  the  highest  amounts  of  total  nitrogen. 
The  legumes  selected  must  have  been  particularly  well  adapted  to  the 
growing  conditions  and  the  soils,  because  the  growth  was  enormous. 
In  the  amount  of  dry  matter  produced  the  parallelism  between  the 
two  legumes  from  soil  to  soil  is  close.    It  is  noteworthy  that  soil  no.  14, 


Wheat 
Bur  Clover 
Oats 
"^Meli  lotus 

26  ^arle^ 


Fig.3£ 

Fig.  32.  Graph  showing  the  total  dry  matter  produced  by  barley,  wheat, 
oats,  rye,  bur  clover,  and  Melilotus  indica  on  the  eight  samples  of  San  Joaquin 
sandy  loam.     First  and  only  crop. 


which  showed  the  highest  total  nitrogen  and  produced  the  most  dry 
matter  from  the  grains,  gave  the  poorest  crop  of  legumes.  The  notes 
taken  during  the  growing  period  show  that  the  relative  appearances 
quite  early  and  throughout  the  period  of  growth  are  usually  a  good 
index  to  the  relative  amounts  of  dry  matter  produced.  This  is  so, 
even  though  the  photographs  of  the  mature  plants  do  not  show  dif- 
ferences nearly  as  great  in  magnitude  as  do  the  dry  weights. 

This  type  does  not  show  any  marked  tendency  for  the  several  soils 
to  approach  a  more  uniform  crop  producing  capacity  through  being 
kept  under  the  same  conditions.  In  fact,  the  second  crop  shows 
greater  variations  than  the  first.  And  this  type  does  not  show  that 
these  nine  soils,  mapped  under  a  single  type  name,  are  closely  similar 
to  one  another  in  crop  producing  power. 


1919]  Pendleton:   A  Study  of  Soil  Types  455 


Table  73 — Hanford  Fine  Sandy  Loam,  Second  Crop 

Wheat  (following  millet) 
Planted,  October  30,  1916.     Harvested,  June  21,  1917 
Straw  Grain  Total  dry  matter 

, A .         . A „     . A . 

r  ^      f  ~\  f  ^ 

No.  Average  Average  Average 

plants     Weight      weight       Weight      weight     Weight     weight  Notes 

3.55  14.30 

2.10  7.30 

10.26         6.45         4.03       21.30       14.30 

1.30  4.65 

1.50  6.35 

3.66         1.10         1.30         3.90         4.96 


Pot 

plants 

Weight 

14-1 

6 

10.75 

14-2 

5 

5.20 

14-3 

6 

14.85 

15-1 

6 

3.55 

15-2 

6 

4.85 

15-3 

6 

2.80 

16-1 

6 

3.20 

16-2 

6 

8.20 

0.95  4.15 

3.70  11.90  Eained  on,  exclud- 

ed from  average 


16-3  6  2.80         3.00         0.70         0.82         3.50         3.82 

0.75 

0.65 

2.60         0.60         0.66 

2.80 

1.55 

4.75       12.90         2.17 

0.90 

0.40 

4.18         0.90         0.73 

1.60 

1.60 

4.46         1.10         1.43 

8.30 

0.90 

3.20         5.40         0.90 

9.05 

0.35 

2.37         0.80         0.57 


19-1 

6 

2.80 

19-2 

6 

2.80 

19-3 

6 

2.20 

20-1 

6 

5.45 

20-2 

6 

4.05 

20-3 

6 

21.35 

22-1 

6 

4.15 

22-2 

6 

3.95 

22-3 

6 

4.45 

23-1 

6 

4.90 

23-2 

6 

4.75 

23-3 

6 

3.75 

24-1 

6 

18.60 

24-2 

6 

3.20 

24-3 

6 

23.75 

25-1 

6 

15.75 

25-2 

6 

2.50 

25-3 

6 

2.25 

3.55 

3.45 

2.80 

3.26 

I 

8.25 

5.60 

34.25 

6.90 

Eained  on,  exclud- 

5.05 

ed  from  average 

4.35 

5.35 

4.92 

6.50 

6.35 

4.85 

5.90 

26.90 

Rained  on,  exclud- 
ed from  average 

4.10 

Rained  on,  exclud- 

29.15 

4.10 

ed  from  average 
Rained  on,  exclud- 

24.80 

ed  from  average 

2.85 

3.05 

2.95 

456  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

Table  74 — Hanford  Fine  Sandy  Loam,  Second  Crop 

Oats  (following  milo  A) 
Planted,  November  22,  1916.     Harvested,  June  18,  1917 
Straw  Grain  Total  dry  matter 

„ A .         , A A „ 

t  ^     r  \  r  "i 

No.  Average  Average  Average 

weight       Weight      weight     Weight     weight  Notes 

2.90  6.70 

1.85  5.25 

3.47         2.40         2.38         5.65         5.86 


Pot 

plants 

Weight 

14-1 

6 

3.80 

14-2 

6 

3.40 

14-3 

6 

3.20 

15-1 

6 

2.45 

15-2 

6 

1.75 

15-3 

6 

2.00 

16-1 

6 

11.15 

16-2 

6 

2.15 

1.85 

5.25 

2.40 

2.38 

5.65 

1.35 

3.80 

1.25 

3.00 

1.50 

1.36 

3.50 

8.40 

19.55 

2.30 

4.45 

3.50         3.43 

Eained  on,  exclud- 
ed from  average 
Pot  saturated  with 
soluble  salts,  ex- 
cluded from  av- 
erage 
16-3  6  1.15         2.15         0.70         2.30         1.85         4.45 


19-1 

6 

1.75 

1.25 

3.00 

19-2 

6 

4.55 

2.95 

7.50 

19-3 

6 

1.35 

2.55 

0.95 

1.72 

2.30 

4.27 

20-1 

6 

10.45 

6.30 

16.75 

Eained  on,  exclud- 
ed from  average 

20-2 

6 

1.55 

1.05 

2.60 

20-3 

6 

1.65 

1.60 

1.00 

1.02 

2.65 

2.62 

22-1 

6 

1.65 

1.10 

2.75 

22-2 

6 

2.10 

1.15 

3.25 

22-3 

6 

2.50 

2.08 

1.50 

1.25 

4.00 

3.33 

23-1 

6 

2.70 

1.55 

4.25 

23-2 

6 

1.90 

1.60 

3.50 

23-3 

6 

3.20 

2.60 

2.00 

1.71 

5.20 

4.32 

24-1 

6 

4.80 

3.10 

7.90 

24-2 

6 

16.75 

9.80 

26.55 

Rained  on,  exclud- 
ed from  average 

24-3 

6 

3.35 

4.07 

2.35 

2.73 

5.70 

6.80 

25-1 

6 

1.95 

1.30 

3.25 

25-3 

6 

2.25 

2.00 

1*40 

1.30 

3.65 

3.30 

25-2 

6 

1.80 

1.20 

3.00 

No. 
plants 

Straw 

Grain                 Total  dry  matter 

K                                                               A 

Pot 

r 

Weight 

Average 
weight 

r                                       y  r                                       y 
Average                     Average 
Weight       weight     Weight     weight 

14-1 

6 

4.75 

4.30                         9.05 

14-2 

6 

9.22 

9.00                       18.22 

14-3 

6 

11.97 

8.65 

10.85         8.05       22.82       16.69 

1919]  Pendleton:   A  Study  of  Soil  Types  457 


Table  75 — Hanford  Fine  Sandy  Loam,  Second  Crop 

Barley  A  (following  cowpeas  A) 
Planted,  October  30,  1916.     Harvested,  May  20,  1917 


Notes 


15-1  6         15.47  15.30  30.77  Kained  on,  exclud- 

ed from  average 
3.29 
4.39         4.12         3.70 

6.42 

2.55 

4.01  1.71  3.56 

1.80 
1.91 

2.70         2.25         1.98 

2.90 

2.80 

3.44         7.45         2.85 

2.07 

3.53 

4.10         2.73         2.78 

3.35 

4.23 

6.24         4.20         3.93 

2.54 

9.75 

3.90         3.57         3.05 

1.75                         4.22  Eained  on,  exclud- 
ed from  average 
Pot  broken,  ex- 
cluded from  av- 
erage 
25-3           6           3.01         2.74         2.18         1.96         5.19         4.70 


15-2 

6 

3.78 

15-3 

6 

5.00 

16-1 

6 

7.28 

16-2 

6 

2.55 

16-3 

6 

2.20 

19-1 

6 

2.82 

19-2 

6 

2.39 

19-3 

6 

2.89 

20-1 

6 

3.57 

20-2 

6 

3.32 

20-3 

6 

19.35 

22-1 

6 

2.73 

22-2 

6 

5.89 

22-3 

6 

3.69 

23-1 

6 

5.29 

23-2 

6 

6.19 

23-3 

6 

7.98 

24-1 

6 

3.07 

24-2 

6 

21.85 

24-3 

6 

4.73 

25-1 

6 

2.47 

25-2 

6 

Lost 

7.07 

9.12 

8.09 

13.70 

5.10 

3.91 

7.57 

4.62 

4.30 

5.14 

4.68 

6.47 

6.12 

26.70 

6.29 

Eained  on,  exclud- 
ed from  average 

4.80 

9.42 

6.42 

6.88 

8.64 

10.42 

12.18 

10.41 

5.61 

31.60 

8.30 

6.95 

458 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


16-3 


Table  76 — Hanford  Fine  Sandy  Loam,  Second  Crop 

Barley  B  (following  soy  beans) 
Planted,  January  31,  1917.     Harvested,  June  21,  1917 


No. 
plants 

Straw 

Grain 

Total  c 
r 

Weight 

Lry  matter 

Pot 

r                                   "\ 
Average 
Weight      weight 

r 
Weight 

Average 
weight 

> 
Average 
weight 

14-1 

6 

9.55 

6.80 

16.35 

14-2. 

6 

6.05 

5.40 

11.45 

14-3 

6 

3.80         6.47 

2.10 

4.76 

5.90 

11.23 

15-1 

6 

3.50 

2.80 

6.30 

15-2 

6 

3.20 

1.70 

4.90 

15-3 

6 

4.05         3.58 

2.60 

2.36 

6.65 

5.95 

16-1 

6 

3.10 

1.45 

4.55 

16-2 

6 

9.20 

8.20 

17.40 

Notes 


7.35 


19-1 

6 

3.05 

19-2 

6 

2.65 

19-3 

6 

2.15 

20-1 

6 

3.35 

20-2 

6 

4.20 

20-3 

6 

2.55 

22-1 

6 

2.05 

22-2 

6 

2.90 

22-3 

6 

3.15 

23-1 

6 

3.10 

23-2 

6 

3.10 

23-3 

6 

3.40 

24-1 

6 

3.10 

24-2 

6 

10.10 

24-3 


3.05 


3.10 


2.62 


3.36 


2.70 


3.20 


2.65 


4.50 

0.80 
2.20 
1.85 

2.60 
3.20 
2.15 

1.75 
2.35 
2.25 

2.05 
2.95 
2.75 

1.45 

5.80 

2.35 


1.45       11.85 


3.85 
4.85 
4.00 


1.61 


2.65 


2.12 


2.58 


1.90 


5.95 
7.40 
4.70 

3.80 
5.25 
5.40 

5.15 
6.05 
6.15 

3.70 
15.90 

5.40 


4.55 


4.23 


6.02 


4.82 


Eained  on,  exclud- 
ed from  average 

Eained  on,  exclud- 
ed from  average 


Eained  on,  exclud- 
ed from  average 


4.55 


25-1 

25-2 
25-3 


3.35 
3.10 
4.70 


3.72 


2.90 
1.85 
4.60 


3.12 


6.25 
4.95 
9.30 


6.83 


1919]  Pendleton:   A  Study  of  Soil  Types  459 


Table  77 — Hanford  Fine  Sandy  Loam,  Second  Crop 

Melilotus  indica  (following  cowpeas  B) 
Planted,  November  22,  1916.     Harvested,  June  21,  1917 


No. 
plants 

Straw 

Unhulled  seed 

A 

Total  d 
Weight 

ry  matter 

Pot 

r 
Weight 

Average 
weight 

r 
Weight 

Average 
weight 

Average 
weight                    Notes 

14-1 

6 

17.00 

15.80 

32.80 

14-3 

6 

13.25 

16.45 

29.70 

14-3 

6 

4.40 

15.12 

3.10 

16.12 

7.50 

31.25     Excluded  from 
average 

15-1 

6 

35.00 

34.75 

69.75 

15-2 

6 

24.85 

27.28 

52.05 

15-3 

6 

28.95 

29.60 

32.70 

31.58 

61.65 

61.15 

16-1 

5 

23.50 

24.90 

48.40 

16-2 

6 

30.80 

25.50 

56.30 

16-3 

6 

23.65 

25.98 

25.70 

25.37 

49.35 

51.35 

19-1 

6 

20.50 

18.35 

38.85 

19-2 

6 

26.90 

23.20 

50.10 

19-3 

6 

26.20 

24.53 

27.40 

22.98 

53.60 

47.52 

20-1 

6 

20.55 

17.80 

38.35 

20-2 

6 

20.75 

21.20 

41.95 

20-3 

6 

28.85 

23.38 

26.05 

21.68 

54.90 

45.07 

22-1 

6 

28.00 

28.10 

56.10 

22-2 

6 

32.30 

34.20 

66.50 

22-3 

6 

28.25 

29.52 

31.85 

31.38 

60.10 

60.90 

23-1 

6 

38.05 

34.25 

72.30 

23-2 

6 

34.40 

36.55 

70.95 

23-3 

6 

32.25 

34.90 

32.35 

34.38 

64.60 

69.28 

24-1 

6 

37.35 

31.40 

68.75 

24-2 

6 

25.90 

28.10 

54.00 

24-3 

6 

29.05 

30.77 

30.15 

29.88 

59.20 

60.65 

25-1 

6 

25.35 

30.45 

55.80 

25-2 

6 

33.90 

35.90 

69.80 

25-3 

6 

32.10 

30.45 

36.65 

34.33 

68.75 

64.78 

460 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table  78 — Hanford  Fine  Sandy  Loam,  Second  Crop 

Bur  Clover  (following  milo  B) 
Planted,  November  22,  1916.     Harvested,  June  25,  1917 


No. 
plants 

Straw 

A 

Burs 

A 

Total  dry 

r 

Weight 

matter 

Pot 

Weight 

Average 
weight 

r 
Weight 

Average 
weight 

Average 
weight 

14-1 

7 

6.70 

17.55 

24.25 

14-2 

6 

7.00 

16.85 

23.85 

14-3 

6 

6.10 

6.60 

14.50 

16.30 

20.60 

22.90 

15-1 

6 

13.30 

29.10 

42.40 

15-2 

6 

14.45 

33.10 

47.55 

15-3 

6 

17.10 

14.95 

26.65 

29.62 

43.75 

44.56 

16-1 

6 

8.85 

15.40 

24.25 

16-2 

6 

12.25 

29.60 

41.85 

16-3 

6 

10.05 

10.38 

21.90 

22.30 

31.95 

32.68 

19-1 

6 

9.90 

19.90 

29.80 

19-2 

6 

7.70 

17.80 

25.50 

19-3 

6 

8.20 

8.60 

22.40 

20.03 

30.60 

28.63 

20-1 

6 

7.90 

22.50 

30.40 

20-2 

6 

9.75 

23.30 

33.05 

20-3 

6 

8.70 

8.78 

20.50 

22.10 

29.20 

30.88 

22-1 

6 

15.90 

38.00 

53.90 

22-2 

6 

13.20 

23.40 

36.60 

22-3 

6 

14.50 

14.53 

31.30 

30.90 

45.80 

45.43 

23-1 

6 

14.45 

37.40 

51.85 

23-2 

6 

13.55 

27.30 

40.85 

23-3 

6 

12.05 

13.35 

28.00 

30.90 

40.05 

44.25 

24-1 

6 

10.60 

24.30 

34.90 

24-2 

6 

12.10 

34.10 

46.20 

24-3 

6 

10.25 

10.98 

24.00 

27.46 

34.25 

38.45 

25-1 

6 

17.90 

40.00 

57.90 

25-2 

6 

14.60 

30.80 

45.40 

25-3 

6 

13.35 

15.28 

26.40 

32.40 

39.75 

47.68 

Notes 


San  Joaquin  sandy  loam. — The  samples  of  this  type  were  the  last 
to  be  weighed  into  pots  and  planted,  because  of  the  lack  of  available 
greenhouse  space ;  therefore  the  time  allowed  for  the  growing  of  but 
one  crop,  instead  of  two,  on  each  pot  of  soil.  The  crops  used  were 
wheat,  barley,  rye,  oats,  bur  clover  (Medioago  sp.),  and  Melilotns 
indioa.  As  was  done  for  the  other  types,  an  excess  of  seed  was 
planted.  When  the  plants  were  well  established,  thinning  reduced 
the  number  to  six  plants  per  pot. 

Since  the  specific  gravity  of  this  soil  was  high,  because  of  the  large 
amount  of  quartz  and  the  small  amount  of  organic  matter  in  its  com- 
position,  six  kilos  of  soil,  instead  of  five,  were  weighed  out  into  each 
pot.  The  samples  of  this  type  have  the  very  annoying  peculiarities 
of  becoming  very  mushy  if  an  excess  of  water  be  added,  and  of  setting 


1919]  Pendleton:   A  Study  of  Soil  Types  461 

with  a  very  hard  surface  on  drjdng.     This  makes  the  soils  hard  to 
handle  in  greenhouse  pot  culture  work. 

The  variation  in  crop  growth  from  soil  to  soil,  as  shown  by  the 
total  dry  matter  produced  (tables  79-84  and  fig.  32),  is  rather 
marked.  That  the  several  samples  do  not  show  equal  crop  producing 
powers  is  very  evident,  though  with  regard  to  the  several  indicator 
crops  the  soils  would  frequently  not  maintain  the  same  order.  Soil 
no.  26  gave  the  poorest  yields  with  all  six  crops.  Except  for  wheat, 
the  soils  nos.  10,  11,  and  12  gave  low  yields  with  both  the  grains  and 
the  legumes.  It  is  interesting  to  note  that  wheat  gave  relatively  high 
yields  with  a  number  of  the  soils,  and  wheat  has  probably  been  raised 
on  these  soils  more  than  any  other  one  crop.  This  series  shows  that, 
as  far  as  the  samples  represent  the  type  and  the  crops  used  represent 
crops  as  a  whole,  the  soils  mapped  under  a  given  type  name  are  not 
closely  similar  in  crop  producing  power  under  greenhouse  conditions. 

Table  79 — San  Joaquin  Sandy  Loam 

Rye 

Planted,  November  22,  1916.     Harvested,  June  21,  1917 


No. 

plants 

Sti 

raw 

Grain 

Total  dry 

r 

Weight 

matter 

Pot 

Weight 

Average 
weight 

r 
Weight 

Average 
weight 

Average 

weight                    Not 

10-1 

6 

1.70 

0.30 

2.00 

10-2 

6 

2.30 

0.35 

2.65 

10-3 

6 

2.05 

2.02 

0.65 

0.43 

2.70 

2.45 

11-1 

6 

3.15 

0.70 

3.85 

11-2 

6 

2.25 

0.70 

2.95 

11-3 

4 

3.20 

2.87 

0.70 

0.70 

3.90 

3.57 

12-1 

6 

1.65 

0.45 

2.10 

12-2 

6 

2.45 

0.85 

3.30 

12-3 

6 

2.40 

2.17 

0.65 

0.65 

3.05 

2.82 

13-1 

6 

4.20 

1.25 

5.45 

13-2 

6 

4.30 

0.80 

5.10 

13-3 

6 

3.75 

4.08 

1.60 

1.22 

5.35 

5.30 

17-1 

6 

7.55 

1.60 

9.15 

Rained  on 

17-2 

6 

1.95 

0.55 

2.50 

17-3 

6 

1.80 

1.87 

0.45 

0.50 

2.25 

2.37 

18-1 

6 

2.35 

0.85 

3.20 

18-2 

6 

0.90 

0.30 

1.20 

18-3 

6 

3.70 

2.32 

1.20 

0.78 

4.90 

3.10 

21-1 

6 

2.20 

0.80 

3.00 

21-2 

6 

2.70 

0.95 

3.65 

21-3 

6 

6.55 

2.45 

2.35 

0.87 

8.90 

3.33     Rained  on 

26-1 

6 

1.50 

0.60 

2.10    . 

26-2 

6 

2.55 

0.75 

3.30 

26-3 

6 

2.50 

2.18 

0.70 

0.68 

3.20 

2.87 

462 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


65 


60 


.35 


50 


45 


40 


85 


30 


25 


20 


15 


10 


/ 
/ 

\ 

1 

V 

__L 

/ 
/ 

\ 
\ 

/ 

\ 

\ 

\ 

T 

1 
1 

/ 

/ 

/ 

\ 
\ 

\ 

1 
1 

/ 

/ 

/ 

N 

^\ 

1 

1 

/  / 

/  / 

/  / 

/  / 

1  / 

\ 

w 

\ 

~~~~~^-':s*-, 

t 

**X' 

"■•"^r.""^ 

marAMk  - 

?C 



^"*        '"•.      *S 

Melilotus 


Bur 
Clover 


Barley  B 

Barley  A 

Oats 

Wheat 


14  15  16  19  20  22  23  24  25  Soils 

Fig.    33.     Graph    showing   the   total   dry   matter   produced  by   wheat,    oats, 

barley    (two  series),  bur  clover,   and  Melilotus  indica  on  the  nine   samples   of 
Ilanford  fine  sandy  loam.     Second  crop. 


1919]  Pendleton:   A  Study  of  Soil  Types  463 


Table  80 — San  Joaquin  Sandy  Loam 
Barley 
Planted,  October  30,  1916.     Harvested,  June  17,   1917 
Straw  Grain  Total  dry  matter 


Pot 

No. 
plants 

r 
Weight 

Average 
weight 

r 
Weight 

Average 
weight 

r 

Weight 

Average 

weight                   Notes 

10-1 

6 

2.93 

0.92 

3.85 

10-2 

6 

1.87 

0.81 

2.68 

10-3 

6 

1.47 

2.09 

0.85 

0.86 

2.32 

2.95 

11-1 

6 

1.91 

0.66 

2.57 

11-2 

6 

2.02 

1.28 

3.30 

11-3 

6 

2.97 

2.30 

0.90 

0.95 

3.87 

3.25 

12-1 

6 

10.27 

4.95 

15.22 

Eained  on;  exclud- 

12-2 

6 

3.60 

1.32 

4.92 

ed  from  average 

12-3 

6 

3.49 

3.54 

0.43 

0.87 

3.92 

4.42 

13-1 

6 

2.14 

1.46 

3.60 

13-2 

6 

3.19 

1.78 

4.97 

13-3 

6 

3.28 

2.87 

1.77 

1.67 

5.05 

4.53 

17-1 

6 

3.89 

2.17 

6.06 

17-2 

6 

3.74 

1.80 

5.54 

17-3 

6 

2.44 

3.35 

0.80 

1.59 

3.24 

4.95 

18-1 

6 

4.65 

1.93 

6.58 

18-2 

6 

3.74 

1.94 

5.68 

18-3 

6 

5.61 

4.66 

2.34 

2.07 

7.95 

6.74 

21-1 

6 

2.05 

1.53 

3.58 

21-2 

6 

2.10 

1.80 

3.90 

21-3 

6 

3.81 

2.65 

2.33 

1.88 

6.14 

4.54 

26-1 

6 

1.12 

0.63 

1.75 

26-2 

6 

1.08 

0.41 

1.49 

26-3 

6 

1.20 

1.13 

0.70 

0.58 

1.90 

1.71 

464  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table  81 — San  Joaquin  Sandy  Loam 

Wheat 

Planted,  October  30,  1916.     Harvested,  June  21,  1917 

Straw  Grain  Total  dry  matter 


Pot 

No. 
plants 

Weight 

Average 
weight 

f 
Weight 

*> 
Average 
weight 

r 

Weight 

Average 

weight                   Not 

10-1 

6 

3.59 

0.85 

4.80 

10-2 

6 

3.45 

0.45 

3.90 

10-3 

6 

6.35 

4.58 

0.75 

0.68 

7.10 

5.26 

11-1 

6 

5.60 

1.15 

6.75 

11-2 

6 

2.75 

0.60 

3.35 

11-3 

6 

3.45 

3.93 

0.70 

0.81 

4.15 

4.75 

12-1 

6 

6.85 

2.00 

8.85 

12-2 

6 

7.50 

1.35 

8.85 

12-3 

6 

4.45 

6.27 

1.35 

1.56 

5.80 

7.83 

13-1 

6 

3.90 

0.85 

4.75 

13-2 

6 

3.25 

0.45 

3.70 

13-2 

6 

3.95 

3.70 

0.75 

0.68 

4.70 

4.38 

17-1 

6 

2.70 

0.25 

2.95 

17-2 

6 

1.20 

0.45 

1.65 

17-3 

6 

2.75 

2.21 

none 

0.23 

2.75 

2.45 

18-1 

6 

5.90 

1.50 

7.40 

18-2 

6 

7.90 

2.40 

10.30 

Rained  on 

18-3 

6 

5.00 

5.45 

1.00 

1.25 

6.00 

6.70 

21-1 

6 

3.10 

1.05 

4.15 

21-2 

5 

4.30 

0.75 

5.05 

21-3 

6 

8.40 

3.70 

2.45 

0.90 

10.85 

4.60     Rained  on 

26-1 

6 

2.35 

0.55 

2.90 

26-2 

6 

0.40 

none 

0.40 

Rained  on 

26-3 

6 

2.60 

2.47 

0.35 

0.45 

2.95 

2.92 

1919]  Pendleton:   A  Study  of  Soil  Types  465 


Table  82 — San  Joaquin  Sandy  Loam 

Oats 

Planted,  November  22,  1916.     Harvested,  June  17,  1917 

Straw  Grain  Total  dry  matter 


Pot 

No. 
plants 

r 

Weight 

Average 
weight 

r 
Weight 

Average 
weight 

Weight 

Average 
weight 

10-1 

6 

2.25 

0.90 

3.15 

10-2 

6 

3.65 

1.90 

5.55 

10-3 

6 

1.70 

2.53 

0.50 

1.10 

2.20 

3.63 

11-1 

6 

2.25 

1.25 

3.50 

11-2 

6 

1.75 

0.95 

2.70 

11-3 

6 

2.10 

2.03 

1.00 

1.07 

3.10 

3.10 

12-1 

6 

1.70 

0.90 

2.60 

12-2 

6 

2.40 

1.00 

3.40 

12-3 

6 

2.35 

2.15 

1.05 

0.98 

3.40 

3.13 

13-1 

6 

2.25 

1.20 

3.45 

13-2 

6 

2.40 

1.10 

3.50 

13-3 

6 

2.70 

2.45 

1.70 

1.33 

4.40 

3.78 

17-1 

6 

0.80 

0.55 

1.35 

17-2 

6 

1.50 

0.90 

2.40 

17-3 

6 

1.25 

1.90 

0.70 

0.72 

1.95 

1.90 

18-1 

6 

1.70 

1.00 

2.70 

18-2 

6 

1.15 

0.60 

1.75 

18-3 

6 

1.10 

1.32 

0.50 

0.70 

1.60 

2.02 

21-1 

6 

1.85 

0.95 

2.80 

21-2 

6 

2.35 

1.05 

3.40 

21-3 

6 

1.00 

1.73 

0.55 

0.85 

1.55 

2.58 

26-1 

6 

1.55 

0.60 

2.15 

26-2 

6 

1.35 

0.80 

2.15 

26-3 

6 

1.65 

1.52 

0.70 

0.70 

2.35 

2.22 

Notes 


466  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Table  83 — San  Joaquin  Sandy  Loam 

Bur  Clover 

Planted,  November  22,  1916.     Harvested,  June  17,  1917 

Straw  Seed  in  burs  Total  dry  matter 


Pot 

No. 
plants 

Weight 

Average 
weight 

r 

Weight 

Average 
weight 

r 

Weight 

Average 

weight                   Notes 

10-1 

6 

0.50 

0.95 

1.45 

10-2 

6 

1.50 

1.65 

3.15 

10-3 

6 

0.50 

0.83 

1.75 

1.45 

2.25 

2.28 

11-1 

6 

0.90 

2.00 

2.90 

11-2 

6 

0.25 

1.00 

1.25 

11-3 

6 

0.30 

0.48 

1.10 

1.37 

1.40 

1.85 

12-1 

6 

0.90 

3.00 

3.90    . 

12-2 

6 

2.15 

5.30 

7.45 

12-3 

6 

1.50 

1.52 

1.90 

3.40 

3.40 

4.92 

13-1 

6 

1.55 

3.45 

5.00 

13-2 

6 

0.75 

2.80 

3.55 

13-3 

6 

4.35 

1.15 

5.70 

3.12 

9.05 

4.27     Excluded  from  av- 
erage 

17-1 

6 

0.70 

2.05 

2.75 

17-2 

6 

2.35 

3.85 

• 

6.20 

Excluded  from  av- 
erage 

17-3 

6 

0.90 

0.80 

1.70 

1.87 

2.60 

2.67 

18-1 

6 

1.20 

3.40 

4.60 

18-2 

6 

3.25 

6.65 

9.90 

Excluded  from  av- 
erage 

18-3 

6 

1.80 

1.50 

4.85 

4.12 

6.65 

5.62 

21-1 

6 

3.35 

3.70 

7.05 

21-2 

6 

2.00 

3.90 

5.90 

21-3 

6 

1.75 

2.37 

5.15 

4.25 

6.90 

6.62 

26-1 

6 

0.60 

1.45 

2.05 

26-2 

6 

1.20 

2.75 

3.95 

26-3 

6 

0.40 

0.73 

1.30 

1.83 

1.70 

2.56 

1919]  Pendleton:   A  Study  of  Soil  Types  467 

Table  84 — San  Joaquin  Sandy  Loam 

Melilotus  indica 

Planted,  November  22,  1916.     Harvested,  June  21,  1917. 


Notes 


No. 
plants 

Sti 

A 

•aw 

Unhull 

ed  seed 

A 

Total  dry 
Weight 

matter 

Pot 

r 
Weight 

Average 
weight 

r 
Weight 

Average 
weight 

Average 

weight 

10-1 

6 

1.20 

1.20 

2.40 

10-2 

6 

1.03 

0.92 

1.95 

10-3 

6 

1.30 

1.18 

1.65 

1.26 

2.95 

2.44 

11-1 

6 

1.05 

0.85 

1.90 

11-2 

6 

0.50 

0.35 

0.85 

11-3 

6 

1.00 

0.85 

0.80 

0.67 

1.80 

1.52 

12-1 

6 

1.07 

2.05 

3.12 

12-2 

6 

1.70 

2.45 

4.15 

12-3 

6 

1.20 

1.33 

1.40 

1.96 

2.60 

3.29 

13-1 

6 

3.05 

3.70 

6.75 

13-2 

6 

3.10 

3.95 

7.05 

13-3 

6 

3.50 

3.22 

4.45 

4.03 

7.95 

7.25 

17-1 

6 

3.05 

4.05 

7.10 

17-2 

6 

2.25 

3.55 

5.80 

17-3 

6 

2.85 

2.72 

3.20 

3.60 

6.05 

6.32 

18-1 

6 

3.25 

3.90 

7.15 

18-2 

6 

2.05 

2.65 

4.70 

18-3 

6 

2.85 

2.42 

3.95 

3.50 

6.80 

6.22 

21-1 

6 

2.50 

3.40 

5.90 

21-2 

6 

2.65 

3.95 

6.60 

21-3 

6 

3.45 

2.87 

3.30 

3.55 

6.75 

6.42 

26-1 

6 

1.10 

0.85 

1.95 

26-2 

6 

0.95 

0.85 

1.80 

26-3 

6 

1.30 

1.12 

1.05 

0.92 

2.35 

2.04 

GENERAL  DISCUSSION 

The  limited  time  available  for  this  study  made  it  impossible  to 
make  all  the  determinations  upon  each  of  the  several  horizons  of  all 
the  soils  collected  for  this  study. 

It  was  believed,  however,  that  the  additional  data  were  not  re- 
quired, since  that  already  at  hand  seemed  to  give  ample  evidence  upon 
which  to  base  conclusions.  Therefore,  in  many  cases  determinations 
were  run  on  the  surface  horizon  only.  This  makes  some  of  the  tables 
appear  incomplete. 


468  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

On  the  basis  of  the  preceding  results  and  discussions  some  general 
treatment  is  possible,  as  well  as  a  more  or  less  critical  discussion  of  the 
methods  of  soil  surveying  pursued  by  the  Bureau  of  Soils. 

The  types  and  the  localities  of  collection  of  the  soils  studied  were 
as  follows : 

Diablo  clay  adobe:  Thalheim  (17) 

San  Juan  Capistrano   (1)  Madera    (18) 

Los  Angeles   (2)  Merced    (21) 

Calabasas   (5)  Del  Mar  (26) 
Danville    (6)                                         Kan  ford  fine  sandy  loam: 

Altamont   clay   loam  Elk  Grove   (14) 

Walnut  (3)  Acampo   (15) 

San  Fernando  Valley  (4)  Woodbridge    (16) 

Mission  San  Jose   (7)  Waterford  (19) 

Sa?i  Joaquin  sandy  loam:  Snelling  (20) 

North   Sacramento    (10)  Basset  (22) 

Lincoln    (11)  Anaheim   (23) 

Wheatland   (12)  Los  Angeles   (24) 

Elk  Grove  (13)  Van  Nuys    (25) 

Note. — Figures  following  localities  designate  sample  numbers. 

Comparisons  of  Physical  Data 

The  mechanical  analyses  of  the  soils  were  carried  out  with  both 
the  Hilgard  elutriator  and  the  Bnrean  of  Soils  centrifuge  methods. 
The  tedious  nature  of  the  elutriator  method  has  been  emphasized  else- 
where. The  results  by  this  method  show  that  the  soils  of  each  type 
as  a  whole  are  somewhat  similar,  though  no  two  are  identical  and 
some  samples  of  a  type  are  widely  divergent  from  the  rest.  The 
Bureau  of  Soils  method  appears  to  give  a  sharper  and  more  satisfac- 
tory separation  into  classes  than  does  the  elutriator  method.  This  is 
to  be  expected  since  the  separates  represent  greater  ranges  of  particle 
sizes.  As  a  check  on  the  texture  of  the  samples  collected,  it  shows  that 
some  of  the  soils  are  not  true  to  name,  therefore  that  all  soils  mapped 
under  a  given  type  name  are  not  closely  similar  to  one  another.  Of 
course,  this  is  the  belief  of  many  soil  surveyors,  but  it  seems  strange 
that  in  the  present  work,  where  there  was  the  attempt  to  select  soils 
representative  of  the  class  and  type  chosen  for  study,  that  such  diver- 
gences developed.  It  is  an  interesting  commentary  on  the  personal 
equation  of  the  field  worker,  in  this  case  of  the  writer,  who  collected 
the  samples. 


1919 j  Pendleton:   A  Study  of  Soil  Types  469 

With  regard  to  the  methods  of  mechanical  analysis,  one  should  not 
overlook  Mohr's  work  on  The  Mechanical  Analysis  of  Soils  of  Java,30 
which  gives  an  excellent  discussion  of  the  relative  merits  of  the  better 
known  systems  of  mechanical  analysis.  He  describes  a  modified  cen- 
trifuge method  preferred  by  him. 

Under  a  discussion  of  the  physical  constants  of  soils,  Free31  dis- 
cusses the  value  of  mechanical  analysis  as  a  soil  constant,  and  shows 
that  there  are  three  serious  errors  in  the  determination,  all  of  which 
impress  themselves  upon  one  making  and  using  such  analyses.  They 
are:  "(1)  disunity  of  expression;  (2)  failure  to  express  conditions 
within  the  limits  of  individual  groups;  and  (3)  failure  to  take 
account  of  variations  in  the  shapes  of  the  particles."  Yet  he  empha- 
sizes, and  rightly  so,  i  l  that  mechanical  analysis  is  by  no  means  useless 
nor  to  be  belittled  as  a  means  of  soil  investigation."32 

Moisture  equivalents. — This  determination  showed  quite  distinct 
averages  for  the  types,  though  there  was  considerable  variation  within 
each  of  the  types.  Eliminating  those  samples  shown  to  be  non-typical 
according  to  the  mechanical  analysis,  the  variation  within  the  type  is 
reduced  considerably.  Yet  it  cannot  be  said  that  as  regards  this  con- 
stant that  all  soils  mapped  under  a  given  type  name,  or  even  those 
soils  under  a  given  type  name  which  the  mechanical  analysis  has 
shown  to  be  true  to  name,  have  closely  similar  moisture  equivalents. 
Briggs  and  McLane33  express  the  belief  that  ultimately  moisture 
equivalent  determinations  will  replace  mechanical  analysis  in  the 
classification  of  soils,  because  the  determination  is  simple  and  the 
result  can  be  expressed  as  a  single  constant. 

Hygroscopic  coefficient. — The  two  heavy  types  show  averages  dis- 
tinct from  those  of  the  two  light  types,  but  the  wide  and  erratic  varia- 
tion within  the  type,  together  with  the  nearly  universal  failure  of 
Briggs  and  Shantz's  formula34  to  convert  these  values  into  values 
even  approximating  those  of  the  moisture  equivalent,  leads  one  to 
doubt  the  accuracy  of  these  figures  of  the  hygroscopic  coefficient.  It 
is  because  of  the  ease  of  determining  the  moisture  equivalent,  and 
because  of  the  difficulties  involved  in  correctly  carrying  out  the  hygro- 
scopic coefficient,  that  the  doubt  is  cast  upon  the  latter  determination. 


so  Bull.  Dept.  of  Agr.,  Indes  Neerland,  1910,  no.  41,  pp.  33. 
3i  Free,  E.  E.,  Studies  in  Soil  Physics,  Plant  World,  vol.   14    (1912),  nos.   2, 
5,  7,  8. 

32  ibid.,  p.  29. 

33  Proc.  Amer.  Soc.  Agron.,  vol.  2  (1910),  pp.  138-47. 

34  U.  S.  Bur.  PI.  Ind.,  Bull.  230  (1912),  p.  72. 


470  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Comparison  of  Chemical  Data 

The  total  nitrogen  content  of  the  samples  of  each  type  varies 
within  somewhat  wide  limits.  The  average  amounts  for  the  several 
types  are  distinct,  though  the  variations  are  such  that  some  of  the 
quantities  of  one  type  overlap  those  of  another  type.  It  is  believed 
that  for  the  types  selected  the  field  differentiations  do  indicate  dif- 
ferences. 

Eegarding  the  humus  content  of  the  four  types  under  considera- 
tion, the  results  are  somewhat  different.  The  average  amounts  of 
humus  are  almost  alike  in  three  of  the  four  types,  while  the  nitrogen- 
poor  San  Joaquin  soil  has  an  average  of  about  half  that  of  the  others. 
Within  the  type  the  soils  may  be  very  nearly  alike  in  the  humus  con- 
tent, as  is  the  case  in  two  of  the  types,  or  may  be  widely  variable,  as 
in  the  Hanford  fine  sandy  loam.  It  should  be  noted  that  the  amount 
of  humus  as  shown  by  the  method  used,  is  not  indicated  by  the  inten- 
sity of  the  color  either  of  the  soil  or  of  the  resulting  extract.  This 
confirms  the  findings  of  Gortner,  which  are  cited  elsewhere. 

There  was  quite  a  wide  range  shown  in  the  results  of  the  deter- 
mination of  the  loss  on  ignition.  The  Diablo  and  Altamont  soils,  be- 
cause of  the  heavier  textures  and  the  relatively  large  amounts  of  com- 
bined water,  and  of  considerable  amounts  of  CaC03  in  at  least  one 
case,  gave  high  losses  on  ignition.  The  averages  were  close,  6.8%  for 
the  Diablo,  and  6.7%  for  the  Altamont.  The  Hanford  soils  were 
lower,  though  with  a  wider  range.  Soil  no.  14,  with  6.9%  loss  on  igni- 
tion, shows  almost  double  that  of  any  other  soil  in  the  type.  The  San 
Joaquin  soils,  with  an  average  of  2.6%,  show  the  lowest  average  loss 
on  ignition.  The  smaller  amounts  of  organic  matter  in  these  soils  is 
one  reason  for  the  smaller  loss.  The  two  heavier  types  have  averages 
close  together,  and  the  lighter  types  have  averages  not  far  apart,  but 
because  of  the  wide  variations  within  each  type,  the  results  of  the 
determination  of  the  loss  on  ignition  certainly  do  not  show  that  all 
soils  classified  in  one  type  are  closely  similar. 

Hall  and  Russell,  in  their  discussion  of  the  soils  of  southeastern 

England,35  consider  of  value  the  ratio  of  Q-. —     — :      A — but  apply- 

%  loss  on  ignition, 

ing  this  ratio  to  the  California  soils  under  consideration  does  not  seem 

to  give  any  relations  of  value.    The  Diablo  ratio  varies  from  0.0136  to 

0.0158,  the  Altamont  from  0.0141  to  0.0204,  the  San  Joaquin  from 

0.0144  to  0.0232,  and  the  Hanford  from  0.011  to  0.0172. 


85  Jour.  Agr.  Sci.,  vol.  4  (11)11),  pp.  182-223. 


1919]  Pendleton:   A  Study  of  Soil  Types  471 

The  calcium  (as  CaO)  content  of  the  soils  is  interesting  especially 
because  of  the  variability.  The  Altamont  samples  show  the  greatest 
variation,  for  the  largest  quantity  of  CaO  is  about  seven  times  the 
smallest.  The  San  Joaquin  samples  are  second,  with  the  largest  over 
six  times  the  smallest.  The  Diablo  samples  are  third,  with  the  largest 
over  five  times  the  smallest,  while  the  Hanford  soils  show  the  least 
variation,  the  largest  being  less  than  twice  the  smallest.  There  are 
quite  marked  differences  between  the  averages  of  the  Diablo,  Alta- 
mont, and  Hanford  soils  (the  San  Joaquin  samples  are  intermediate), 
but  the  wide  variations  within  the  types  greatly  minimize  any  sig- 
nificance the  averages  might  have.  Hence  it  is  not  possible  to  state 
that  one  or  another  type,  as  represented  by  these  samples,  is  charac- 
terized by  high,  low,  or  moderate  amounts  of  calcium. 

As  the  analyses  of  the  samples  for  calcium  failed  to  point  out  any 
striking  characteristics,  unless  it  be  that  of  variability,  so  it  is  with 
magnesium.  Magnesium  (as  MgO)  is  variable  within  each  of  the  four 
types.  The  largest  quantity  is  about  three  times  the  smallest  in  the 
Diablo,  San  Joaquin,  and  Hanford  types,  while  in  the  Altamont  the 
largest  is  twenty-seven  times  the  smallest.  Considering  the  Hanford 
and  San  Joaquin,  or  the  Diablo  and  San  Joaquin,  it  is  seen  that  the 
curves  do  not  overlap,  while  the  Diablo  and  Altamont,  or  the  Diablo 
and  Hanford  curves  do.  The  averages  of  the  four  types  are  distinct, 
except  between  the  Hanford  and  Diablo,  which  are  quite  close.  But, 
here  again,  because  of  the  more  or  less  wide  range  of  values  within 
each  of  the  types,  the  averages  are  of  little  significance.  The  lime- 
magnesia  ratio  is  very  variable  in  these  soils.  Comparing  the  calcium 
and  magnesium  curves  for  the  several  soils  gives  a  good  idea  of  the 
relations.  The  Diablo  curves  are  quite  similar  except  for  soil  no.  6, 
which  shows  3%  MgO  and  0.5%  CaO.  In  the  Altamont  soils  the 
curves  are  somewhat  similar  in  direction,  though  the  ratios  differ 
widely.  In  the  Hanford  and  San  Joaquin  types  the  ratios  of  CaO  and 
MgO  are  also  far  from  constant,  yet  it  is  readily  seen  from  the  graphs 
that  the  amount  of  magnesium  varies  more  or  less  directly  with  the 
amount  of  calcium. 

Respecting  the  total  phosphorus  (as  P205),  if  the  San  Joaquin  and 
Hanford  samples  alone  be  considered,  there  would  be  no  doubt  as  to 
the  significance  of  the  field  separation,  the  variations  within  the  type 
notwithstanding.  But  when  the  other  two  types  are  considered,  the 
case  is  not  so  good  in  favor  of  the  field  classification.  The  Diablo  soils 
show  considerable  variation  in  the  amount  of  Pr,02,  while  the  three 


472  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

Altamont  samples  show  much  variation.  Therefore  with  reference  to 
the  amount  of  phosphorus,  and  the  types  studied,  the  separation  into 
types  may  or  may  not  be  of  significance. 

If  the  results  of  the  potassium  (K20)  determinations  are  com- 
pared, it  is  very  evident  that  but  one  conclusion  can  be  drawn,  and 
that  is  that  the  variations  in  the  amount  of  potassium  within  each 
type  are  great  enough  so  that  any  differences  between  the  averages 
of  the  several  types  have  no  significance  whatsoever.  Therefore,  with 
regard  to  total  potassium  the  field  separation  of  soils  as  represented 
by  these  twenty-four  samples  of  four  types  means  nothing. 

Comparison  of  Bacteriological  Data 

The  wealth  of  the  data  obtained  from  over  nine  hundred  bacteri- 
ological tumbler  cultures  is  hardly  of  sufficient  significance  to  com- 
pensate for  the  effort  involved.  There  is  one  outstanding  conclusion 
from  all  this  work,  namely,  the  lack  of  any  very  definite,  distinct,  and 
constant  bacteriological  activity  of  the  samples  of  one  type  that  is  not 
to  a  considerable  extent  shared  by  the  samples  of  the  other  types. 
There  are  tendencies  in  certain  types  with  regard  to  bacteriological 
activity  which  show  that  some  of  the  types  as  a  whole  are  more  or  less 
distinct  from  one  or  more  of  the  others. 

Ammonification. — The  amount  of  ammonia  produced  from  dried 
blood  varies  to  a  great  extent.  The  Altamont  samples  gave  between 
10  and  33  mg.  nitrogen  as  ammonia;  the  Diablo  samples  gave  between 
7  and  26  mg.,  and  the  Hanford  samples  gave  between  35  and  72  mg. 
The  Altamont  and  Diablo  types  are  thus  seen  to  be  about  alike  in  their 
low  ammonifying  power,  as  compared  with  the  higher  ability  of  the 
San  Joaquin  types  and  still  greater  ability  of  the  Hanford  types. 
And  since  there  are  somewhat  greater  variations  between  the  types 
than  between  the  samples  of  a  given  type,  the  ammonifying  power 
may  be  significant. 

Nitrogen  fixation. — The  two  heavy  types,  Diablo  clay  adobe  and 
Altamont  clay  loam,  show  no  characteristic  differences,  while  the  two 
lighter  types  show  considerable  differences.  As  a  whole  the  types  are 
different  one  from  another,  yet  the  variations  within  the  type  are 
sufficient  to  prevent  any  statement  that  the  rate  of  nitrogen  fixation 
is  a  function  of  the  type  as  determined  in  the  field,  or  vice  versa. 

Nitrification. — The  nitrification  data  are  the  most  puzzling.  The 
figures  are  extremely  variable  within  a  given  type ;  the  erratic  way 


1919]  Pendleton:   A  Study  of  Soil  Types  473 

in  which  the  Hanford  samples  behave  is  not  paralleled  by  any  other 
type.    There  are  certain  ways  in  which  the  types  are  distinct : 

The  nitrification  of  the  soil's  own  nitrogen  as  compared  with  the 
soil's  action  upon  added  nitrogen  is  in  some  degree  separate  for  each 
type.  The  San  Joaquin  samples  nitrified  their  own  nitrogen  to  a 
greater  degree  than  they  did  the  nitrogen  added  to  the  soil. 

The  relative  nitrification  of  the  several  nitrogenous  materials 
(dried  blood,  cottonseed  meal,  ammonium  sulfate)  is  in  some  measure 
distinct  for  the  several  types.  The  Diablo,  Altamont,  and  San  Joaquin 
types  show  ammonium  sulphate  to  be  nitrified  the  best,  cottonseed  meal 
less,  and  dried  blood  still  less.  The  Hanford  samples  show  cottonseed 
meal  to  give  the  highest  percentage  of  nitrates,  with  dried  blood  less, 
and  ammonium  sulfate  still  less. 

When  any  one  soil  is  compared  through  the  three  sets  of  deter- 
minations there  are  no  apparent  similarities.  The  Hanford  type 
shows  the  greatest  bacterial  activity,  while  the  San  Joaquin  shows 
less,  with  the  heavier  types  showing  sometimes  greater  activity  and 
sometimes  less  than  that  of  the  San  Joaquin. 

Work  in  Other  States 

In  connection  with  the  original  chemical  work  reported  in  this 
paper,  there  should  be  mentioned  the  large  amount  of  work  done  in  a 
number  of  states  on  the  analysis  of  the  types  of  soils  as  mapped  by 
the  Bureau  of  Soils.  Apparently,  these  analyses  have  been  made 
without  any  question  as  to  the  validity  of  the.  existing  subdivisions 
into  types.  The  various  analyses  have  been  reported  with  some  com- 
ment, but  that  which  does  appear  usually  deals  with  the  "adequacy" 
or  "  inadequac3T "  of  the  plant  food  present.  Blair  and  Jennings36 
present  a  large  amount  of  data  on  chemical  composition,  some  of 
which  on  rearrangement  show  interesting  relationships  (table  85). 
From  the  data  the  four  series  of  soils  with  the  largest  number  of 
analyses  were  selected  (see  following  table).  Under  each  series  there 
are  from  2  to  4  soil  tj^pes,  and  from  2  to  6  analyses  under  each  type. 
The  averages  from  each  type  are  tabulated,  also  the  averages  of  all 
the  types  within  the  series.  This  is  both  for  the  strong  acid  extraction 
and  the  fusion  methods  of  analysis  for  significant  plant  food  elements. 
There  are  no  doubts  but  that  each  series  of  soils  shows  characteristic 
chemical  peculiarities,  peculiarities  which  are  to  a  great  extent  con- 


36  The  Mechanical  and  Chemical  Composition  of  the  Soils  of  the  Sussex  Area, 
New  Jersey,  Geol.  Surv.  N.  J.,  Bull.  10,  1910. 


474 


University  of  California  Publications  in  Agricultural  Sciences        [Vol.3 


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1919]  Pendleton:   A  Study  of  Soil  Types  475 

stant  throughout  the  several  representatives  of  the  type.  In  some 
cases,  the  differences  or  similarities  are  more  clearly  seen  in  the  total 
analyses,  and  in  other  cases,  they  appear  in  the  acid  analyses  and  not 
in  the  fusion  analyses.  Within  any  series  the  variations  between 
analyses  of  any  one  type  are  about  the  same  as  the  variations  from 
type  to  type.  There  are  many  other  papers37  which  provide  material 
for  similar  comparisons. 

A  paper  by  Van  Dyne  and  Ashton38  reports  chemical  analyses  for 
lime,  phosphoric  acid,  potash,  and  nitrogen  on  the  samples  collected 
in  the  course  of  the  survey  of  Stevens  County,  Washington.  Though 
sometimes  there  is  a  much  greater  range  within  a  type  than  between 
types,  in  a  general  way  the  analyses  for  any  one  type  agree  quite 
well.  As  a  whole  the  chemical  analyses  seem  to  show  that  the  field 
criteria  are  also  a  basis  for  grouping  soils  into  certain  chemical 
groups.  It  should  be  mentioned  that  the  work  of  Blair  and  Jennings, 
also  that  of  Van  Dyne  and  Ashton,  deals  with  individual  areas,  and 
not  with  samples  from  several  scattered  areas.  The  work  of  Fraps  and 
Williams,  and  the  original  work  here  reported  represent  scattered 
areas. 


The  Greenhouse  Cultures 

By  far  the  most  interesting  results  were  obtained  in  the  pot  culture 
work.  It  is  realized  that  there  are  variations  in  the  physical  nature 
of  the  samples  of  a  given  type,  yet  since  these  samples  were  collected 
with  considerable  care  by  one  familiar  with  field  classifications,  the 
samples  so  selected  should  be  fairly  representative  of  the  type.  It  is 
probable  that  if  all  the  soils  in  each  of  the  types  used  were  exactly  the 
same  in  texture,  i.e.,  if  the  mechanical  analysis  showed  the  same 
results  for  the  several  soils,  the  crops  produced  on  the  several  soils  of 
a  type  would  be  less  divergent  in  appearance  or  weight.  Yet  it  is 
not  at  all  likely  that  the  crops  would  be  the  same.  Pot  cultures  pre- 
sume that  the  conditions  in  all  the  pots  can  be  kept  uniform,  but  this 
is  obviously  impossible.  Greenhouse  work  is  subject  to  many  interfer- 
ing factors.     Nevertheless,  the  results  are  believed  to  be  significant, 


37  Williams,  and  others,  Eeport  on  the  Piedmont  Soils,  North  Carolina  Dept. 
Agr.,  Bull.  206,  1915. 

Fraps,  G.  S.,  Composition  of  the  Soils  of  South  Texas,  Texas  Agr.  Exp.  Sta., 
Bull.  161,  1913;  Composition  of  the  Soils  of  the  Texas  Panhandle,  ibid.,  Bull. 
173,   1915. 

38  Van  Dyne  and  Ashton,  Soil  Survey  of  Stevens  County,  Washington,  Field 
Operations,  U.  S.  Bur.  Soils,  1913,  pp.  2165-2295. 


476  University  of  California  Publications  in  Agricultural  Sciences        [Vol.3 

despite  the  large  correction  that  the  consideration  of  the  probable 
error  might  introduce. 

The  differences  in  the  crop  producing  power  of  the  soils  are  very 
marked  in  the  Diablo  clay  adobe,  where  the  second  crop,  as  well  as 
the  first,  shows  evident  variations  in  the  ability  to  support  a  crop. 
In  the  Altamont  clay  loam  the  second  crop  almost  loses  the  variations 
seen  in  the  first  crop  from  pot  to  pot.  The  samples  of  both  types 
seem  to  show  one  thing  in  common — the  approach  of  the  several  sam- 
ples toward  a  uniform  ability  to  produce  crops,  as  the  soils  are  kept 
for  longer  periods  under  the  same  conditions.  The  Hanford  soils  did 
not  show,  with  the  several  crops,  the  parallelism  in  the  fertility  from 
crop  to  crop  as  did  the  Diablo  and  Altamont  soils.  Some  soils  pro- 
duced good  crops  of  grain  and  poorer  crops  of  legumes,  others  did  the 
opposite.  The  low  nitrogen  content  in  this  type  seemed  to  be  a  limit- 
ing factor.  This  would  account  for  the  variation  between  the  grain 
and  the  leguminous  crops.  Also,  the  presence,  or  absence  of  Bacillus 
radicuola  inoculation  in  this  connection  might  greatly  affect  the  total 
crop  produced. 

There  does  not  seem  to  be  much  doubt  but  that  the  soils  of  the 
several  types  compared  in  this  way  are  not  the  same,  though  they  are 
in  certain  respects  similar. 

The  Place  of  Soil  Classification. — With  all  these  evidences  that  the 
soils  within  the  several  types  are  not  closely  similar,  though  they  are 
classified  the  same  by  the  Bureau  of  Soils,  what  conclusion  is  one  to 
reach  as  to  the  value  of  such  a  classification  ?  If  it  were  true  that  there 
were  no  appeal  from  the  findings  of  such  laboratory  and  greenhouse 
<l<-1<'rminations  as  these,  and  that  these  determinations  were  a  final 
proof  of  the  fertility  or  infertility  of  a  soil,  obviously  there  would  be 
but  one  thing  to  do — discard  all  such  field  classifications  as  useless. 
But  the  writer  is  one  of  a  great  many  soilists  who  are  not  willing  to 
rely  on  laboratory  or  even  greenhouse  results  for  an  absolute  deter- 
mination of  fertility,  and  for  the  grouping  together  of  soils  into  a 
workable  classification.  Not  enough  is  definitely  known  as  to  the  mean- 
ing of  such  findings,  though  there  are  certainly  many  valuable  points 
shown  by  laboratory  analyses.89 

As  examples  of  the  value  of  natural  classifications  we  may  con- 
sider those  of  botany,  /oology,  or  mineralogy.  If  available,  a  wholly 
satisfactory  classification  of  soils  would  be  equally  useful.    The  appre- 


89  Jordan,  W.   H.,  Measurements  of  Soil  Fertility,  New  York  Agr.  Exp.  Sta. 
Geneva',  Bull.  424,  L916. 


1919]  Pendleton:   A  Study  of  Soil  Types  477 

ciation  of  this  is  shown  in  the  many  systems  of  soil  classification  that 
have  been  proposed. 

Despite  the  foregoing  facts  that  have  been  obtained  showing  the 
divergent  properties  of  different  samples  of  one  type  presumabi}' 
alike,  yet  it  must  be  admitted  that  soil  surveys,  even  such  as  are  no 
more  refined  than  those  of  the  Bureau  of  Soils,  have  considerable 
value  for  field  use. 

It  is  felt  that  the  additional  effort  required  to  modify  the  practices 
of  the  Bureau  of  Soils  in  the  mapping  and  classifying  of  soils  would 
be  more  than  justified  by  the  increased  accuracy  and  usefulness  of 
the  maps.  To  point  out  some  of  the  causes  of  the  present  practices 
and  to  give  suggestions  for  possible  methods  of  improvement,  the 
following  discussion  of  the  Bureau  of  Soils  methods  has  been 
prepared. 

Discussion  of  the  Bureau  of  Soils'  methods. — The  methods  of  map- 
ping and  classifying  soils,  as  devised  and  used  by  the  Bureau,  have 
resulted  from  some  definite  and  important  considerations. 

1.  The  necessity  for  keeping  down  the  cost  of  surveying  and  map- 
ping prevents  the  use  of  laboratory  and  culture  methods  in  the  study 
of  the  soils  classified,  even  if  it  were  not  for  the  fact  that  one  of  the 
outstanding  policies  of  the  Bureau  apparently  denies  the  validity  of 
such  studies  in  the  classification  of  soils.  This  does  not  include  the 
mechanical  analysis  of  soils,  which  is  not  a  separate  laboratory  deter- 
mination, but  a  method  of  checking  the  field  man's  decision  as  to  the 
texture.  It  should  also  be  added  that  some  of  the  reports  as  published 
in  the  Field  Operations  of  the  Bureau  of  Soils,  for  1913,  show  the 
subdivision  of  the  soils  into  two  groups  based  upon  the  CaC08  content. 
Keeping  down  the  cost  has  also  prevented  the  use  of  sufficient  time  to 
map  the  soils  correctly,  even  according  to  the  criteria  admittedly  of 
value  in  the  system  adopted.  Many  of  the  other  methods  of  classify- 
ing and  mapping  soils,  even  if  applicable  to  most  of  the  agricultural 
regions  of  the  United  States,  would  be  absolutely  out  of  the  question 
on  account  of  cost. 

2.  The  large  and  widely  diversified  area  of  the  United  States,  and 
the  attempt  to  map  representative  areas  in  various  parts  of  the  coun- 
try, early  led  to  difficulties.  There  seemed  to  be  a  lack  of  understand- 
ing as  to  what  criteria  to  use  in  the  classification  of  the  soils.  Re- 
cently, some  of  the  areas  first  mapped  in  the  state  of  California  have 
been  resurveyed.  The  texture,  series,  and  province  differences  of  the 
early  mapping  seem  not  to  have  been  clear.    For  example,  we  may  con- 


478  University  of  California  Publications  in  Agricultural  Sciences        [Vol.3 

sider  the  differences  between  the  older  and  the  recent  survey  of  two 
localities  east  of  Los  Angeles.  The  notes  were  made  by  C.  J.  Zinn, 
a  member  of  the  party  which  made  the  recent  survey : 

Locality  A — About  15  square  miles  with  Eaton  Wash  on  the  west,  center  of 
Monrovia  on  the  east,  mountains  on  the  north,  and  a  line  about  3  miles  south  of 
mountains  as  the  south  boundary.  The  old  survey^  has  four  types  of  three  series 
and  two  miscellaneous  types:  San  Gabriel  gravelly  loam,  San  Gabriel  gravelly 
sand,  Placentia  sandy  loam,  San  Joaquin  black  adobe,  and  Eiverwash  and  Moun- 
tains. The  new  survey  (1915,  unpublished)  has  13  types  of  6  series  and  3  mis- 
cellaneous types:  Hanford  stony  sand,  gravelly  sand,  loam,  sandy  loam,  fine 
sandy  loam,  and  sand;  Tejunga  stony  sand;  Zelzah  loam  and  stony  loam;  Pla- 
centia loam,  Holland  loam,  Chino  loam  and  silt  loam.  The  miscellaneous  types 
are  Eough  Mountain  land,  Eough  Broken  land,  and  Eiverwash. 

Locality  B — In  the  city  of  Pasadena,  comprising  about  3.5  square  miles,  with 
the  southwest  corner  at  the  center  of  the  city.  The  old  survey41  shows  San 
Gabriel  loam  occuping  about  0.6  of  the  area,  San  Gabriel  gravelly  sand  about  0.3, 
and  Placentia  sandy  loam  about  0.1.  The  new  survey  (1915,  unpublished)  shows 
Zelzah  gravelly  loam  occupying  about  0.9  of  the  area,  Zelzah  loam  about  0.1,  with 
a  very  small  body  of  Holland  loam.  The  older  survey  showed  a  recent  alluvial 
soil  where  the  recent  one  shows  an  old  valley  filling  soil. 

Besides  these  errors  (detected  as  such  by  the  practical  man,  who 
might  attempt  to  use  the  soil  maps  in  the  field)  there  are  in  addition 
those  of  another  nature  which  were  the  source  of  much  criticism  in  the 
earlier  history  of  the  survey — the  so-called  "procrustean  classification" 
criticism  of  Hilgard.42  Due  apparently  to  an  insufficient  study  of  the 
soils  of  the  United  States,  there  was  the  attempt  to  classify  in  the  same 
series  soils  of  widely  differing  properties — differences  of  an  important 
nature  being  ignored. 

At  the  present  time  there  is  an  increasing  tendency  toward  limit- 
ing series  groups  of  soils  to  a  more  or  less  definite  climatological 
region.  In  this  connection  see  the  later  changes  in  the  correlation  of 
many  soils.43  These  changes  tend  to  limit  the  geographic  range  of  the 
series,  and  make  these  series  narrower  and  more  exact.  Moreover,  it 
is  understood  that  as  the  knowledge  of  the  soils  has  increased,  the 
changes  in  correlation  have  been  proceeding  rapidly  since  the  above 
list  was  issued.  This  indicates  that  as  the  facts  accumulate  the  "pro- 
erustean  classification"  criticism  is  losing  its  force. 


40  Field  Operations  of  the  U.  S.  Bur.  of  Soils,  1901,  San  Gabriel  sheet. 

4i  Ibid. 

« Hilgard,  E.  W.,  arid  Loughridge,  R.  H.,  Proc.  Second  Intern.  Agrogeol. 
Conf.,  Stockholm,  1910,  pp.  228-29;  Hilgard,  E.  W.,  U.  S.  Office  Exp.  Sta.,  Bull. 
142  (1904),  p.  119;  Hilgard,  E.  W.,  Proc.  First  Intern.  Agrogeol.  Conf.,  Budapest, 
1909,  y.p.  52-54. 

M  II.  S.  Bur.  Soils,  Bull.  90,  1913. 


1919]  Pendleton:   A  Study  of  Soil  Types  479 

3.  There  was  a  lack  of  trained  men  early  in  the  work.  This  was 
to  be  expected.  As  has  been  shown,  the  early  surveys  were  very  crude 
in  certain  places.  It  must  be  added  that  some  of  the  errors  and  omis- 
sions made  in  the  more  recent  maps  are  not  due  to  a  lack  of  training, 
but  to  the  carelessness  of  the  field  men  with  respect  to  details. 

4.  The  policy  of  the  Bureau  has  been  to  recognize  the  physical 
characteristics  of  the  soil  as  factors  in  fertility  to  the  virtual  exclusion 
of  the  chemical  or  biological  factors.  Therefore  the  use  of  physical 
criteria  is  necessary.  Besides,  the  criteria  must  be  such  as  can  be 
applied  in  the  field,  and  are:  "(1)  color,  (2)  texture,  determined  by 
rubbing  between  the  thumb  and  finger,  (3)  structure,  (4)  nature  of 
subsoil,  (5)  presence  of  hardpan,  (6)  height  of  water  table,  (7)  pres- 
ence of  alkali,  (8)  topography,  (9)  physiographic  form  and  hence 
mode  of  formation,  and  (10)  source  of  material  (sedimentary,  igne- 
ous, or  metamorphic  rocks).  Humus,  and  the  presence  or  absence  of 
appreciable  quantities  of  lime,  also  the  reaction  of  the  soil  (acid  or 
alkaline)  are  frequently  guessed  at.  These  criteria  are  practically 
the  only  ones  that  can  be  applied  in  field  work.  It  is  believed  that 
these  same  criteria  indicate  the  chemical  nature  of  the  soil,  though 
there  has  been  no  attempt  to  correlate  some  of  the  factors.  However, 
the  original  work  reported  in  this  paper  would  indicate  that  the  chem- 
ical nature  is  not  the  same,  of  soils  classified  the  same  by  the  Bureau 
of  Soils  criteria. 

5.  The  desire  to  limit  the  number  of  groups  of  soils  is  a  wholly 
sound  one.  In  discussing  the  problems  of  classifying  soils  there 
should  always  be  kept  in  mind  the  fact  that  some  of  the  problems  are 
not  very  different,  fundamentally,  from  some  of  the  problems  that 
have  been  causing  perplexity  among  biologists  for  a  long  while. 
The  tendency,  as  seen  in  some  of  the  recent  surveys,  to  make  the 
series  more  inclusive  and  to  introduce  the  term,  phase,  is  heartily 
commended.  By  making  the  series  broader  there  will  be  less  difficulty 
in  placing  a  soil  in  its  proper  group.  The  phase  will  take  care  of  many 
of  the  series  differences  between  area  and  area. 

6.  It  seems  certain  that  if  there  were  more  emphasis  placed  upon 
the  inspection  of  the  area,  during  the  progress  of  the  field  work  and 
after  its  completion,  there  would  be  a  much  closer  approach  to 
accuracy  throughout  the  map  and  report.  At  the  present  time  the 
field  man  is  not  closely  checked  up.  The  careless  or  indifferent  worker 
can  map  more  or  less  as  he  pleases,  especially  in  the  out-of-the-way 
places. 


480  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

7.  Whether  the  soil  survey  should  include  more  than  a  simple 
classification  of  the  soils  or  not,  is  an  unsettled  question.  It  is  thought 
hardly  possible  that  in  a  soil  survey  the  field  man  could  handle  all  the 
phases  of  an  agricultural  survey  of  an  area,  when  his  energies  should 
be  fully  employed  in  the  classification  of  the  soils.  It  is  believed  that 
the  place  of  the  survey,  in  this  country  at  least,  is  to  handle  the 
classification  of  the  soils,  leaving  the  study  of  the  remaining  factors 
largely  to  other  specialists,  who  would  use  the  soil  survey  as  a  basis.44 
But  to  make  the  soil  maps  of  more  general  use  for  such  work,  they 
must  be  more  accurate.  These  maps  never  can  become  the  basis  of 
other  agricultural  studies  as  long  as  many  experiment  station  workers 
ridicule  them.  Hence,  the  ultimate  effort  of  the  survey  should  be 
toward  better  work,  rather  than  covering  a  wide  range  of  agricultural 
studies. 

8.  There  is  not  the  incentive  to  make  as  many  separations  of  the 
soils  in  the  field,  as  the  field  man  might  think  best,  because  frequently 
the  feeling  of  the  editors  is  that  there  would  be  too  many  small  bodies 
of  soil  shown  on  the  manuscript  maps  which  would  not  warrant  the 
additional  cost  of  publication. 

In  conclusion,  the  Bureau  of  Soils'  system  has  much  to  commend 
it  as  a  field  method,  and  the  resulting  maps  and  classification  are  be- 
lieved to  be  of  distinct  value.  It  is  felt  that  a  more  general  under- 
standing of:  (1)  the  limitations  under  which  the  maps,  the  earlier 
ones  especially,  have  been  made;  (2)  the  difficulties  under  which  the 
field  work  is  at  present  carried  on;  (3)  the  meaning  of  the  correlation 
of  soils;  and  (4)  the  general  policy  of  the  Bureau  of  Soils  would  give 
people  more  sympathy  with  their  work. 


44Fippin,  E.  O.,  Proc.  Amer.  Soc.  Agron.,  vol.  1   (1908),  pp.  191-97. 


1919]  Pendleton:   A  Study  of  Soil  Types  481 


SUMMARY 

Presumably  typical  samples  of  four  soil  types  were  collected  for 
laboratory  and  greenhouse  study  from  widely  distributed  localities  in 
the  state  of  California.  The  field  appearance  of  each  sample  was 
usually  sufficient  to  warrant  the  classification  as  it  exists. 

Physical  Relations 

1.  The  mechanical  analysis  by  the  Hilgard  elutriator  shows  that 
the  soils  of  a  given  type  are  in  some  cases  quite  divergent  from  each 
other  in  their  content  of  certain  of  the  sizes  of  particles.  The  mechan- 
ical analysis  by  the  Bureau  of  Soils  method  shows  that  6  of  the  24 
soils  were  not  true  to  their  type  names,  and  that  of  those  soils  within 
the  type  there  is  considerable  variation. 

2.  The  moisture  equivalents  for  the  several  types  show  distinct 
enough  values  to  substantiate  the  field  separation. 

3.  The  hygroscopic  coefficients  vary  widely  within  each  type  and 
the  types  are  not  shown  to  be  distinctly  different  by  this  criterion. 

Chemical  Relations 

1.  The  total  nitrogen  averages  vary  markedly  from  type  to  type, 
with  the  Altamont  clay  loam  containing  three  times  that  in  the  San 
Joaquin  sandy  loam. 

2.  The  average  humus  content  of  the  San  Joaquin  samples  is 
about  half  that  of  the  other  types.  The  variations  in  the  humus  con- 
tent between  the  types  are  small,  considering  the  diverse  nature  of  the 
types  and  the  large  range  in  the  amount  of  humus  within  the  type. 

3.  The  loss  on  ignition  shows  a  considerable  variation  within  the 
type  and  no  significant  distinction  between  the  four  types. 

4.  The  average  total  calcium  content  of  the  types  is  distinct, 
though  the  wide  range  within  each  type  minimizes  the  significance  of 
the  variation  in  the  averages. 

5.  With  regard  to  magnesium,  the  types  are  neither  distinct  nor 
are  the  soils  within  the  type  closely  similar. 

6.  The  average  phosphorus  content  of  the  types  is  distinct,  though 
the  ranges  within  the  several  types  frequently  overlap. 

7.  The  total  potassium  results  do  not  show  the  types  to  be  distinct 
nor  the  soils  within  a  type  closely  similar. 


482  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 


Bacteriological  Relations 

1.  The  ammonifying  power  shows  rather  larger  variations  from 
type  to  type  than  between  the  samples  of  a  type. 

2.  The  nitrogen  fixation  data  do  not  show  characteristic  differences 
for  the  several  types. 

3.  Regarding  nitrification  as  a  whole  there  may  be  a  greater 
divergence  between  the  samples  of  a  type  than  between  types.  The 
relative  nitrification  of  the  soil's  own  nitrogen  varies  with  the  type, 
as  does  the  relative  nitrification  of  the  several  nitrogenous  materials 
added. 

Pot  Cultures  in  the  Greenhouse 

In  addition  to  the  effect  of  the  probable  error,  the  impossibility 
under  the  conditions  herein  described  of  growing  the  same  crops  on 
all  the  soils,  during  the  same  season  of  the  year  in  the  greenhouse, 
prevents  close  comparisons  between  the  types,  or  between  the  first  and 
second  crops  on  a  given  soil.  The  comparison  of  several  samples  of  a 
given  soil  type  and  the  comparisons  of  various  soil  types,  according 
to  the  previously  outlined  greenhouse  methods  show  that : 

1.  Different  representatives  of  a  given  type  are  not  the  same  in 
their  ability  to  produce  crops. 

2.  The  arrangement  of  the  samples  of  a  given  type  according  to 
their  fertility  may  or  may  not  vary  with  the  special  crops  used  as  the 
indicators. 

3.  The  types  are  distinct  with  respect  to  their  fertility,  considering 
their  average  production. 

Therefore  it  is  concluded  that  with  regard  to  the  24  soils  of  4 
types  examined,  all  soils  mapped  under  a  given  name  by  the  Bureau 
of  Soils  method  may  or  may  not  be  closely  similar,  depending  upon 
the  criteria  used.  The  greater  number  of  the  criteria  show  the  soils 
of  a  type  to  be  not  closely  similar,  and  the  types  to  be  but  litle  differ- 
entiated from  each  other. 

In  connection  with  the  results  of  the  author's  study  of  the  soils, 
there  is  given  an  historical  sketch  of  the  development  of  soil  classifica- 
tion and  mapping,  also  a  discussion  of  certain  of  the  methods  em- 
ployed by  the  Bureau  of  Soils  of  the  United  States  Department  of 
Agriculture.  It  is  pointed  out  that  despite  its  defects,  the  work  of 
the  Bureau  of  Soils  is  of  value,  and  is  practically  the  only  type  of  soil 
classification  and  mapping  possible  under  the  conditions  imposed. 


1919]  Pendleton:   A  Studij  of  Soil  Types  483 

APPENDIX  A 
METHODS  AND  TECHNIQUE 

Collection  of  Samples 

There  was  difficulty  in  finding  types  that  would  meet  the  requirements  of  wide 
distribution  and  of  differing  from  one  another  as  to  series  as  well  as  texture.  The 
types  chosen  were: 

Diablo  clay  adobe,  a  residual  soil. 

Altamont  clay  loam,  a  residual  soil. 

San  Joaquin  sandy  loam,  an  "old  valley  filling"   (old  alluvial  soil). 

Hanford  fine  sandy  loam,  a  recent  alluvial  soil. 

The  first  task  was  the  collection  of  the  samples  of  soil  for  study  in  the  labora- 
tory and  in  the  greenhouse.  Of  course,  there  were  kept  in  mind  the  errors  and 
difficulties  involved  in  the  collection  of  representative  samples.  The  selection  of 
the  localities  in  which  to  collect  samples  was  frequently  made  in  consultation  with 
the  persons  who  had  originally  mapped  the  areas  under  the  Bureau  of  Soils. 
This  was  done  so  that  the  soil  chosen  might  as  nearly  as  possible  represent  what 
the  surveyor  had  in  mind  as  characteristic  of  the  type  within  the  area.  It  was  to 
be  expected  that  the  ideal  type  which  one  man  would  use  as  a  guide  as  he  did  the 
mapping  in  one  area  would  not  always  be  identical  with  that  which  another  man 
might  use  in  mapping  another  area,  despite  the  aid  of  the  inspector  in  keeping  the 
ideal  types  of  the  field  men  as  nearly  alike  as  possible.  Some  of  the  accompanying 
index  maps,  showing  the  places  where  the  soil  samples  were  collected,  are  dupli- 
cates of  the  same  locality.  As  the  dates  show,  one  is  a  portion  of  a  less  recent, 
and  the  other  of  a  more  recent  survey.  In  many  cases  the  index  maps  have  been 
copied  from  the  manuscript  maps,  a  number  of  surveys  in  this  state  not  yet  being 
published.  For  a  discussion  of  the  differences  in  these  maps,  see  below  the  section 
on  The  Criticism  of  the  U.  S.  Bureau  of  Soils  Method  of  Surveying. 

Not  only  were  the  field  men  questioned  about  the  locality,  but  as  nearly  as 
possible  an  exact  designation  was  obtained  on  the  soil  map  itself.  In  the  collec- 
tion of  some  of  the  samples  the  writer  had  the  good  fortune  to  have  the  assistance 
of  the  man  or  men  who  actually  mapped  the  soils  in  question.  Sometimes  there 
was  no  trouble  at  all  in  locating  a  typical  body  of  the  soil  where  a  sample  might 
be  taken.  On  the  other  hand,  as  in  the  case  of  the  collection  of  the  Hanford  fine 
sandy  loam  from  Woodbridge  (nos.  15  and  16),  more  than  two  hours  were  spent 
in  driving  about,  trying  to  find  a  place  that  seemed  a  typical  fine  sandy  loam. 
Experience  shows  that  the  personal  equation  in  field  work  is  very  important  and 
is  hard  to  control.45 

No  special  attempt  was  made  to  obtain  virgin  soil,  for  the  types  of  soils  that 
had  been  selected  for  study  were  mainly  agricultural,  and  most  of  the  soils  have 
been  at  some  time  under  cultivation,  if  they  are  not  now.  Also,  there  has  been 
little,  if  any  modification  of  the  agricultural  soils  by  the  addition  of  fertilizers. 
Hence  the  small  tracts  of  the  Hanford  fine  sandy  loam,  for  instance,  that  are  still 
virgin  are  largely  non-agricultural,  waste  land  areas,  and  would  not  illustrate  the 
properties  of  the  type  as  a  whole.  Not  so  large  a  part  of  the  San  Joaquin  sandy 
loam  is  under  cultivation  now,  though  almost  all  of  it  has  been  farmed  to  grain 
in  the  past.  The  two  minor  types  studied,  the  Altamont  clay  loam  and  the  Diablo 
clay  adobe,  being  of  residual  origin  and  occupying  rolling  to  hilly  or  mountainous 
land  are  also  not  very  extensively  farmed.  The  topography  is  the  limiting  factor 
in  most  cases. 


45  Fippin,  E.  O..  Practical  Classification  of  Soils,  Proc.  Amer.  Soc.  Agron.,  vol.  3  (1911), 
pp.  76-89 ;  Increasing  the  Practical  Efficiency  of  Soil  Surveys,  Proc.  Amer.  Soc.  Agron., 
vol.   1    (1907-1909),   pp.   204-06. 


484  University  of  California  Publications  in  Agricultural  Sciences        [Vol.3 

The  ideal  way  to  collect  a  representative  sample  of  soil  for  laboratory  studies 
is  to  make  a  number  of  borings  scattered  about  the  field  or  fields,  so  that  the  sam- 
ple will  approximate  an  average.  But  in  the  case  of  collecting  the  samples  for  this 
study  it  was  considered  best  not  to  attempt  such  a  procedure,  for  the  reason  that 
it  was  desired  to  have  the  samples  for  the  greenhouse  work  and  for  the  physical, 
chemical,  and  bacteriological  studies,  come  from  the  same  lot  of  soil.  The  collec- 
tion of  such  a  large  amount  of  soil,  about  250  pounds  in  all,  from  a  number  of 
places  about  the  selected  field  would  be  very  tedious.  Hence  as  nearly  a  typical 
place  as  possible  Avas  selected,  close  to  a  wagon  road,  in  order  that  the  samples 
could  be  transported  readily.  Care  was  used  that  the  location  be  far  enough  out 
into  the  field  to  allow  the  sample  to  be  representative  of  the  conditions  in  the  field. 

The  subsequent  procedure  was  as  follows:  The  selected  spot  was  cleared  of 
grass  or  other  surface  material  or  accumulation  that  did  not  belong  to  the  soil. 
A  hole  was  dug,  usually  one  foot  deep  (the  depth  depending  entirely  upon  the 
nature  of  the  surface  soil  and  any  noticeable  changes  toward  the  subsoil),  and 
big  enough  to  give  sufficient  soil  to  make  up  the  greenhouse  sample  of  from  225 
to  250  pounds.  The  soil  was  shoveled  directly  into  tight  sugar  or  grain  sacks,  no 
attempt  being  made  to  mix  the  sample  at  this  time.  Some  sacks  of  the  soil  would 
contain  more  of  the  surface  material,  and  others  more  of  the  lower  portion,  but  a 
later  thorough  mixing  and  screening  at  the  greenhouse  gave  a  uniform  sample. 
After  the  large  sample  was  collected,  the  hole  was  usually  dug  two  feet  deeper, 
giving  a  hole  three  feet  deep.  One  side  of  this  hole  was  made  perpendicular,  and 
from  this  side  the  small  samples  were  collected.  The  A,  B,  and  C  horizons  were 
marked  off  on  this  wall,  and  the  samples  collected  by  digging  down  a  uniform 
section  of  the  designated  portion,  using  a  geologic  pick  and  catching  the  loosened 
material  on  a  shovel.  About  ten  pounds  of  soil  were  so  collected,  and  placed  in 
clean,  sterile  canvas  sample  sacks.  Care  was  used  not  to  contaminate  the  samples, 
so  that  the  bacterial  flora  might  remain  nearly  unaltered.  It  seemed  imprac- 
ticable to  attempt  to  collect  the  laboratory  sample  under  absolute  sterile  condi- 
tions, especially  since  some  of  the  deeper  (B  and  C)  samples  were  obtained  by 
means  of  the  soil  auger.  When  the  auger  was  used  to  collect  the  samples  from 
greater  depths  the  boring  was  done  from  the  bottom  of  the  hole  made  in  collect- 
ing the  larger  sample.  The  size  of  the  laboratory  sample  required  the  boring  of 
five  or  six  holes  with  the  usual  1.5  inch  soil  auger.  The  laboratory  sample  of  the 
first  foot,  or  the  A  sample,  was  always  collected  from  the  side  of  the  large  hole. 
Notes  regarding  the  sample,  field  condition,  the  place  of  collection,  together  with 
photographs  and  marked  maps  are  given  in  appendix  B. 

As  described  above,  the  soils  were  collected  in  separate  portions  from  the  sur- 
face to  the  12  inch,  from  the  12  to  24  inch  depth,  and  from  the  24  to  36  inch 
depths  where  there  were  no  abrupt  or  marked  changes  in  the  color,  texture,  or  the 
like,  as  in  the  Hanford  fine  sandy  loam.  But  since  in  some  cases,  as  most  fre- 
quently in  the  San  Joaquin  sandy  loam,  the  samples  do  not  represent  the  first, 
second,  or  third  foot  depths,  as  the  case  might  be,  the  term,  horizon,  has  been 
used.  Horizon  A  indicates  the  surface  sample,  horizon  B  the  second  sample,  and 
horizon  C  the  third  sample. 


Laboratory  Preparation  of  Samples 

The  large  samples  were  stored  in  the  greenhouse  until  ready  for  use.  The  lab- 
oratory samples  were  allowed  to  remain  in  the  sacks  until  air  dry,  when  they  were 
passed  through  a  2  mm.  screen.  This  was  a  difficult  matter,  with  the  heavy  soils, 
as  well  as  with  the  heavy  subsoils  of  the  San  Joaquin  sandy  loam.     Cautious  use 


1919 J  Pendleton:   A  Study  of  Soil  Types  485 

of  the  iron  mortar  "was  necessary  to  supplement  the  rubber  pestle.40  The  samples 
were  thoroughly  mixed  after  screening,  when  they  were  weighed  and  placed  in 
sterile  containers — glass  jars  and  large  bottles.  Precautions  were  taken  as  far 
as  possible  to  avoid  contamination  of  the  samples  during  this  preparatory  process. 
The  screens,  mortars,  scoop,  and  pans  were  flamed  out  between  samples.  Obvi- 
ously contamination  could  not  be  avoided  absolutely  without  too  great  a  prolonga- 
tion of  the  work. 

The  material  not  passing  the  2  mm.  screen  was  subsequently  washed  on  the 
screen,  with  a  stream  of  water  to  remove  the  finer  material.  The  residue  not 
passing  the  screen  by  this  treatment  was  dried  and  weighed.  It  seemed  unneces- 
sary to  adopt  elaborate  precautions,  like  those  described  by  Mohr,47  to  obtain  the 
exact  quantities. 

Mechanical  Analysis 

The  Hilgard  elutriator  was  used  for  the  purpose  of  making  the  mechanical 
analysis  of  the  samples  (surface  horizon  only).  For  the  purpose  of  this  work 
the  method  described  by  Hilgard48  has  been  modified  in  several  respects.  The  pre- 
liminary preparation  by  sifting  through  the  2  mm.  sieve  in  the  dry  state,  and 
through  the  0.5  mm.  sieve  by  the  aid  of  water  was  used.  One  hundred  grams  was 
sifted  with  the  0.5  mm.  sieve,  and  the  fine  material  plus  the  water  was  evaporated 
to  dryness  on  the  water  bath.  The  dry  material  was  broken  up  and  from  this 
the  samples  were  weighed  out  for  the  analysis. 

The  samples  were  not  disintegrated  by  boiling,  since  it  was  believed  that  such 
treatment  would  affect  the  "colloid"  content  of  the  sample.  Instead,  the  samples 
were  shaken  with  water  in  sterilizer  bottles  for  three  hours,  similar  to  the  treat- 
ment preparatory  to  the  mechanical  analysis  by  the  Bureau  of  Soils  method. 
However,  not  boiling  the  samples  caused  more  work  later. 

The  colloidal  clay  was  removed  by  placing  the  previously  shaken  sample  in  a 
large  precipitating  jar  and  stirring  up  with  several  liters  of  distilled  water.  (Dis- 
tilled water  was  used  throughout  the  analysis.)  The  quantity  of  water  was  not 
important,  but  rather  the  depth  of  the  suspension,  which  was  200  mm.  After 
allowing  to  stand  for  24  hours  the  supernatant  turbid  water  was  siphoned  off, 
when  the  residue  in  the  bottom  of  the  jar  was  again  stirred  up  with  water  and 
the  clay  again  allowed  to  settle  out  of  a  200  mm.  column.  This  was  repeated 
until  the  supernatant  liquid  contained  practically  no  material  in  suspension  after 
standing  for  24  hours.  The  clay  suspensions  were  placed  in  large  enamelware 
preserving  kettles,  and  the  solutions  reduced  in  volume  by  boiling.  The  final 
evaporations  were  carried  on  over  the  water  bath,  so  as  to  avoid  too  high  a  tem- 
perature. 

A  large  portion  of  the  finest  sediment  (0.25  mm.  hydraulic  value)  was  removed 
as  follows :  After  the  greatest  portion  of  the  clay  had  been  removed  by  the  24 
hour  sedimentation  and  decantation,  the  sample  was  placed  in  a  1  liter  beaker  and 
stirred  up  with  sufficient  water  to  make  a  100  mm.  column.  After  standing  6 
to  8  minutes  the  suspended  material  was  decanted  off.  This  was  repeated  until 
the  supernatant  solution  was  practically  clear.  The  entire  time  for  these  decanta- 
tions  usually  occupied  2.5  or  3  hours.  The  decanted  material  was  allowed  to  stand 
for  24  hours,  as  before,  and  the  200  mm.  column  decanted  as  with  the  original 
clay  suspension.     This  was  continued  until  the  clay  was  practically  all  removed. 


46  Hilgard,  Calif.  Agri.  Exp.   Sta.,   Circ.   6,   June,   1903. 

47  Bull.  Dept.  Agr.  Indes  Neerland.,  no.  41,   1910. 

48  Calif.   Agr.  Exp.   Sta.,   Circ.   6    (1903),  pp.   6-15;    see  also  Wiley,   Agricultural  Analysis, 
vol.    1    (1906),   pp.   246-62. 


486  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

The  residue  constituted  the  main  portion  of  the  0.25  mm.  hydraulic  value  sep- 
arate. The  residue  from  the  6  to  8  minute  decantation  was  placed  in  the  elutri- 
ator, and  separated  by  the  usual  method  into  the  various  sizes.  Since,  however, 
the  sample  was  not  prepared  by  boiling  previous  to  the  separation  of  the  clay,  the 
clay  was  never  as  thoroughly  removed  from  the  coarser  particles  and  the  finer 
aggregate  particles  were  not  completely  broken  down.  Hence  when  the  sample 
was  placed  in  the  elutriator  and  subjected  to  the  violent  agitation  of  the  stirrer 
an  appreciable  amount  of  clay  passed  off  with  the  finest  separate.  Therefore, 
instead  of  allowing  the  water  to  return  to  the  carboy  from  the  settling  bottle, 
during  the  running  off  of  the  finest  separate,  the  following  procedure  was  em- 
ployed: The  water  was  run  into  precipitating  jars  and  allowed  to  stand  for  24 
hours,  and  the  clay  water  was  then  decanted  off  and  boiled  down  with  the  other 
clay  water. 

A  further  modification  of  the  Hilgard  method  was  found  advisable  after  the 
change  from  the  large  elutriator  tube  to  the  small  one,  preparatory  to  running  off 
the  coarser  separates.  The  mechanical  defects  in  the  elutriator  always  allowed 
for  the  collection  of  a  portion  of  the  sample  in  crevices  where  the  stream  of  water 
could  not  reach  to  carry  off  the  particles.  Hence,  when  the  large  tube  was 
removed,  and  cleaned,  there  was  found  an  appreciable  amount  of  the  finer  sedi- 
ments that  had  not  passed  over.  These  were  all  added  to  the  small  tube  of  the 
elutriator,  and  the  additional  material  of  the  smaller  sizes  run  off,  using  an  hour 
or  so  for  each  size.  This  seemed  a  better  method  than  the  separation  of  such 
sediments  by  the  beaker  method,  as  was  done  by  Dr.  Loughridge. 

The  separates,  after  decanting  most  of  the  water,  were  dried  first  on  the  water 
bath  and  later  in  the  drying  oven  at  100°C-110°C  and  weighed.  All  of  the  deter- 
minations were  made  on  the  water  free  basis.49 


Additional  Physical  Determinations 

Upon  the  surface  or  A  horizon  samples  of  the  24  soils  considered  in  this  study 
additional  physical  determinations  were  made  by  the  Division  of  Soil  Technology, 
through  the  courtesy  of  Professor  Charles  F.  Shaw.  These  determinations  were 
of  the  mechanical  analysis  by  the  Bureau  of  Soils  method,50  of  the  moisture  equiva- 
lent by  the  Briggs  and  McLane  method,51  and  of  the  hygroscopic  coefficient  accord- 
ing to  Hilgard 's  method.52 


Chemical  Methods 

At  first  the  chemical  work  was  based  upon  the  ' '  strong  acid  extraction ' J 
method,  so  well  known  through  the  work  of  Dr.  Hilgard.53  There  are  some  very 
pertinent  objections,  as  well  as  advantages,  to  the  method  of  acid  extraction  for 
the  purpose  of  comparing  soils  among  themselves.54 

in  the  analysis  2.5  gram  samples,  air  dry,  were  used  throughout.  The  acid 
extraction  results  are  not  included  in  this  paper. 


49  The  writer  wishes  to  emphasize  the  tedium  of  the  elutriator  process,  and  to  advise 
Strongly  against  the  use  of  the  apparatus  for  the  comparison  of  the  soils  as  to  texture.  The 
elutriator  is  excellent  from  a  theoretical  point  of  view,  but  the  results  do  not  at  all  warrant 
the  extravagant  use  of  time  in   the  laboratory  that  the   apparatus   requires. 

""('.    8.   Bur.   Soils,    Bull.    84,    1912. 

"''  Ibid.,   Bull.  45,   1907;    Proc.  Amer.  Soc.  Agron.,  vol.  2    (1910),  pp.    138-47. 

02  Calif.  Agr.  Exp.  Sta.,  Circ.  6    (1903),  p.   17;   Soils,  pp.   197-99. 

"Calif.    Agr.    Kxp.    Sta.,   Circ.   6    (1903),  pp.    16ff;    Soils,   pp.    340ff. 

:A  Sec   Ilissink,    Intern.  Mitt,  fur  Bodenkunde,   vol.   5    (1915),   no.    1. 


1919]  Pendleton:   A  Study  of  Soil  Types  487 

The  sodium  peroxide  fusion  method55  was  carried  out  on  the  two  larger  series 
of  soils,  the  Hanford  and  the  San  Joaquin.  The  elements  sought  were  phosphorus, 
calcium,  and  magnesium.  Five  gram  samples,  air  dry,  were  used  throughout. 
The  general  method  of  analysis,  as  set  forth  by  Hopkins,  Avas  employed,  though 
there  were  a  number  of  refinements  used  to  increase  the  accuracy  of  the  results. 
As  such  might  be  mentioned  the  double  precipitation  of  the  iron,  aluminum,  and 
phosphorus. 

Phosphorus  was  determined  volumetrically,  according  to  the  method  of  Hib- 
bard.56 

Total  nitrogen  was  determined  by  the  modified  Gunning-Kjeldahl  method, 
using  ten  gram  samples. 

Loss  on  ignition  was  determined  upon  the  10  gram,  air  dry  samples  that  were 
used  for  the  determination  of  the  hygroscopic  moisture  of  the  samples  used  in 
the  chemical  analysis.  The  soils  were  ignited  in  a  muffle  furnace  to  constant 
weight. 

Humus  was  determined  by  the  Grandeau-Hilgard  method,57  using  10  gram 
samples,  air  dry. 

Potassium  was  determined  by  the  J.  Lawrence  Smith  method,  using  one  gram 
samples. 

Bacteriological  Methods 

The  only  bacteriological  methods  employed  were  the  determination  by  the  tum- 
bler or  beaker  method  of  the  ammonifying,  the  nitrifying,  and  the  nitrogen  fixing 
powers  of  the  soils.58    All  cultures  were  run  in  duplicate. 

Ammonification  tests  were  made  using  50  grams  of  soil  and  2  grams  (4%)  of 
dried  blood.  The  checks  were  distilled  at  once,  and  the  cultures  kept  in  the  incu- 
bator at  24°C-30°C  for  one  week.  (The  incubator  thermostat  was  unsatisfactory 
in  its  action,  hence  the  variation  in  the  temperature.) 

The  nitrifying  power  of  the  soil  was  tested  as  regards  the  soil's  own  nitrogen, 
dried  blood,  cottonseed  meal,  and  ammonium  sulfate.  In  the  Diablo  clay  adobe 
and  the  Altamont  clay  loam  50  grams  of  soil  were  used,  to  which  was  added  1 
gram  (2%)  of  dried  blood,  or  of  cottonseed  meal,  or  0.1  gram  (0.2%)  of  am- 
monium sulfate.  In  the  case  of  the  San  Joaquin  sandy  loam  50  grams  of  soil  were 
used,  together  with  1  gram  (2%)  of  dried  blood  or  of  cottonseed  meal,  or  0.2  gram 
(0.4%)  of  ammonium  sulfate.  In  the  series  run  on  the  Hanford  fine  sandy  loam 
100  grams  of  soil  were  used,  to  which  were  added  1  gram  (1%)  of  dried  blood  or 
of  cottonseed  meal  or  0.2  gram  (0.2%)  of  ammonium  sulfate.  It  is  to  be  regret- 
ted that  the  several  series  could  not  all  be  run  on  exactly  the  same  basis  as  the 
Hanford  series.  But  the  small  amount  of  stock  soils  of  the  samples  of  the  earlier 
series  precluded  the  use  of  larger  original  samples,  not  to  speak  of  the  impossi- 
bility of  repeating  these  series.  The  cultures  were  incubated  for  four  weeks  at 
24°C-30°C.  At  the  end  of  this  period  the  cultures  were  dried  in  the  oven  at  about 
90  °C  and  the  nitrate  content  determined  by  the  phenoldisulfonic  acid  method 
according  to  the  modifications  of  Lipman  and  Sharp.59 

Nitrogen  fixation.  For  this  determination  uniform  quantities  of  soil  were 
used  throughout — 50  grams,  to  which  was  added  1  gram  of  mannite.     These  cul- 


55  Hopkins,    Soil   Fertility   and   Permanent   Agriculture,    pp.    630-33;    Hopkins    and    Pettit, 
Soil  Fertility  Laboratory  Manual   (Boston,  Ginn,   1910),  pp.  42-45. 

56  Jour.  Ind.  Eng.  Chem.,   vol.   5,  pp.  993-1009. 
"Calif.  Agr.  Exp.   Sta.,  Circ.  6    (1903),  p.  21. 

58  Burgess,   P.    S.,    Soil   Bacteriology   Laboratory  Manual,    Easton,    Pa.,   The   Chemical   Pub- 
lishing Co.,    1914. 

59  Univ.  Calif.  Publ.  Agr.  Sci.,  vol.  1   (1912),  pp.  21-37. 


488  University  of  California  Publications  in  Agricultural  Sciences        [Vol.3 

tures  were  incubated  for  four  weeks  at  24°C-30°C,  at  the  end  of  which  time  bac- 
terial action  was  stopped  by  drying  in  the  oven  for  24  hours.  Subsequently,  the 
samples  were  broken  up  in  a  mortar,  and  10  grams  weighed  out  for  the  determina- 
tion of  the  total  nitrogen. 


Pot  Cultures  in  the  Greenhouse 

The  large  samples  of  the  surface  foot  of  soil  were  stored  in  the  greenhouse 
until  used.  The  preparation  of  the  samples  was  in  most  cases  as  follows:  The 
sample  was  placed  on  a  large  table  and  screened  through  a  quarter  inch  sieve. 
This  treatment  of  screening  was  attempted  with  the  Diablo  clay  adobe  and  the 
Altamont  clay  loam,  but  was  abandoned  as  practically  hopeless.  The  samples  of 
these  two  types  had  been  collected  in  the  late  summer,  when  the  ground  was  very 
hard  and  dry,  hence  the  clods  defied  any  efforts  to  break  them  up.  As  an  alterna- 
tive the  samples  were  as  thoroughly  mixed  as  possible  and  weighed  out  into  the 
pots.  Several  waterings  during  a  week,  together  with  carefully  breaking  up  the 
lumps  by  hand,  rendered  the  soils  finely  divided  enough  to  permit  the  planting  of 
the  seeds.     The  Hanford  and  San  Joaquin  types  were  readily  screened. 

All  the  soils  were  weighed  out  into  nine  inch  flower  pots.  In  most  cases  the 
pots  had  been  previously  paraffined.  Care  was  taken  to  clean  the  pots  thor- 
oughly, as  far  as  surface  material  was  concerned;  many  of  the  pots  were  scrubbed 
with  a  brush  and  water.  All  previously  used  pots  were  examined  to  exclude  the 
use  of  such  as  had  formerly  been  used  for  soils  containing  high  percentages  of 
soluble  salts,  but  such  examination  was  not  always  successful  in  eliminating  the 
undesirable  pots,  as  was  afterwards  evident.  In  the  Diablo,  Altamont,  and  Han- 
ford soils  the  quantity  of  soil  used  was  five  kilos  per  pot.  In  the  San  Joaquin 
soils  six  kilos  were  used. 

Enough  soil  was  collected  to  fill  eighteen  pots.  This  would  allow  for  the 
arrangement  of  six  sets  of  triplicates  of  every  sample;  and  the  planting  of  a  dif- 
ferent crop  in  each  of  the  sets  would  allow  for  the  growing  simultaneously  of  six 
different  crops  on  every  soil.  For  example,  there  were  placed  together  in  the 
greenhouse  and  considered  as  a  unit  in  the  culture  work  the  series  of  the  Diablo 
clay  adobe,  including  three  pots  of  the  sample  taken  from  San  Juan  Capistrano, 
three  from  that  taken  near  Los  Angeles,  three  from  that  of  the  San  Fernando 
valley,  and  lastly  three  from  the  sample  taken  in  the  Danville  region.  This  group 
of  pots  was  planted  to  oats,  barley,  bur  clover,  or  any  one  other  crop.  The  pots 
were  kept  together  in  the  greenhouse,  that  the  conditions  for  each  one  in  the  set 
would  be  as  nearly  uniform  as  possible,  for  even  a  slightly  different  location  in 
the  greenhouse  was  found  to  affect  the  crop  appreciably.  The  other  five  sets  of 
pots  were  similarly  treated.  No  fertilizing  materials  were  added  to  any  of  the 
soils.  All  were  used  in  their  normal  condition.  The  aim  was  to  compare  the  crop 
producing  power  of  the  representatives  of  a  given  type  of  soil  from  various 
localities. 

Several  crops  were  grown,  as  the  desire  was  to  get  a  series  of  plants  that 
would  grow  well  under  greenhouse  conditions,  and  act  as  indicators.  It  was 
known  that  barley  was  about  the  best  crop  to  use,  but  supplementary  plants  were 
desired.  Barley,  wheat,  oats,  rye,  millet,  milo,  cowpeas  (black  eye  beans),  soy 
beans,  beans  (small  white),  bur  clover  (Mcdicago  denticulata) ,  sweet  clover  (Meli- 
lotus  indica),  and  oats  and  bur  clover  in  combination  were  tried.  Some  were 
a  marked  success  under  greenhouse  conditions,  and  others  were  practically  total 
failures;  the  better  crops  were  given  by  barley,  soy  beans,  bur  clover,  and  millet. 
Sweet  clover  gives  excellent  results.     This  wide  range  of  varieties  of  plants  was 


1919]  Pendleton:   A  Study  of  Soil  Types  489 

necessary  because  of  the  fact  that  it  was  desired  to  grow  two  crops  a  year  on  the 
soils.  The  winter  crops  will  not  do  well  in  summer,  and  vice  versa,  even  though 
the  summers  in  Berkeley  are  relatively  cool,  and  though  the  greenhouse  was 
whitewashed  during  the  summer  months. 

The  seed  was  obtained  in  most  cases  from  the  Division  of  Agronomy  of  the 
Department  of  Agriculture  of  the  University  of  California.  Such  varieties  as 
were  not  available  from  this  source  were  obtained  from  the  commercial  seed 
houses  in  San  Francisco. 

Usually  the  seed  was  planted  directly  in  the  pots,  using  sufficient  seed  to  be 
sure  that  enough  would  germinate  and  grow  to  give  the  desired  number  of  plants 
per  pot,  usually  six.  After  the  plants  were  well  established,  and  before  there  was 
any  crowding  in  the  pots,  the  plants  were  thinned.  In  some  cases  an  insufficient 
number  of  plants  germinated  to  give  the  desired  number  per  pot.  Difficulty  was 
found  in  getting  the  soy  beans  and  cowTpeas  to  germinate,  especially  in  the 
heavier  soils.  This  was  overcome  by  sprouting  the  seeds  in  an  incubator  and 
planting  them  when  the  radicle  was  half  an  inch  long  or  more.  An  excellent  stand 
was  thus  obtained. 

Xo  actual  measurements  of  the  height  of  the  plants,  or  the  length  of  leaves 
were  made  in  the  greenhouse  work.  But  photographs  were  taken,  and  in  these 
photographs  the  attempt  was  made  to  secure  representative  records  of  the  entire 
series,  without  photographing  the  crop  in  every  pot.  The  usual  procedure  in  the 
Altamont  and  Diablo  series  was  to  photograph  two  pots  out  of  each  set  of  tripli- 
cates, an  attempt  being  made  to  select  average,  representative  pots.  In  the  large 
Hanford  series  one  representative  pot  of  each  set  of  triplicates  in  each  crop 
series  was  photographed,  and  three  representative  sets  of  triplicates  were  also 
photographed.     Thus  some  of  the  pots  appear  twice,  and  allow  of  comparisons. 

If  any  doubt  be  entertained  as  to  the  relative  weights  of  the  crops  in  the  pots 
photographed  as  compared  with  those  not  so  recorded,  the  relative  weights  of  the 
crops  may  be  easily  obtained  by  referring  to  the  tables  of  dry  weights.  In  prac- 
tically every  case  the  pot  label  can  be  read  from  the  photograph.  The  method  of 
labeling  is  exemplified  as  follows: 

6     Soil  sample  no.  6  (Diablo  clay  adobe  from  Danville). 

W     Wheat,  first  crop. 
2     Pot  2  of  the  triplicate  set  first  planted  to  wheat. 

CP     Cowpeas,  second  crop. 

During  the  growth  of  the  crops,  notes  were  taken  as  to  the  relative  growths  and 
the  general  conditions  of  the  plants. 

When  the  crop  had  ceased  growing  it  was  harvested,  whether  or  not  it  was 
mature  in  the  sense  of  having  set  and  developed  seed.  The  plants  from  a  given 
pot  were  put  in  a  paper  bag,  labeled,  and  placed  in  the  drying  oven  for  2!  hours. 
The  plants  were  weighed  when  dry  and  cool.  If  any  mature  seed  was  produced 
it  was  weighed  separately. 

Between  the  first  and  second  crops  the  soil  was  allowed  to  rest  from  two  to 
three  weeks  or  longer.  Each  pot  was  emptied  and  the  soil  passed  through  a 
quarter  inch  screen  before  replacing  in  the  pot.  This  broke  up  the  lumps  and 
removed  most  of  the  roots.  The  roots  were  not  saved.  The  weight  of  the  roots 
would  have  been  interesting,  but  their  recovery,  especially  from  the  heavy  soils, 
would  have  involved  careful  washing,  and  the  loss  of  much  of  the  soil.  It  was 
thought  that  some  washing  would  be  necessary,  even  in  the  Hanford  series,  in 
order  that  the  resulting  figures  might  be  at  all  accurate. 


490  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

APPENDIX  B 
SOIL  SAMPLE  LOCATIONS 

Field  Notes  on  the  Soil  Samples  Collected 

No.  1 — Diablo  Clay  Adobe 
Location:  A  little  over  a  mile  east  of  San  Juan  Capistrano,  Orange  County.  On 
the  lower  slopes  of  the  hills  to  the  south  of  San  Juan  Creek.  Sample  sta- 
tion is  on  a  little  shoulder  running  northwest,  between  Mr.  Echenique's 
house  and  the  fence  following  the  road  to  Prima  Deshecka  Canada.  Ap' 
proximately  one-quarter  mile  from  the  above  house. 
Soil:    0-12  inches — Dark  gray  adobe;  much  cracked. 

12-36   inches — Soil   becomes   gradually   lighter    in    color,   approaching    a   light 

bluish  gray  mottled  Avith  brown. 
36  inches — The  subsoil  becomes  a  silty  clay  loam  in  the  lower  depths. 
History:    The  field  was  pastured  up  to  and  including  1906.     From  1907  to  date 
the  field  has  been  annually  planted  to  barley.     Data  from  Mr.  Echenique, 
the  owner.     Sample  collected  August  19,  1917. 
Depths  of  horizons: 

1-A        0-12  inches.  1-B       12-24  inches.  1-C       24-36  inches. 

No.  2 — Diablo  Clay  Adobe 

Location:  One  and  three-quarter  miles  east  of  southeast  of  Eastlake  Park,  Los 
Angeles.  Station  is  0.7  mile  by  secondary  road  south  of  Pacific  Electric 
railroad  crossing,  and  1.2  miles  southeast  of  the  Southern  Pacific  railroad 
crossing.  Station  is  about  150  feet  up  the  hill  to  the  west  of  the  road,  in 
grain  field,  and  75  feet  south  of  a  10  or  12  year  old  eucalyptus  grove. 
The  road,  going  south,  emerges  from  the  grove,  and  is  then  flanked  by  pep- 
per trees. 

Soil:    0-12  inches — Dark  gray  to  almost  black,  but  with  a  shade  of  brown  rather 
than  a  bluish  gray. 
12-24  inches — Dark  grayish  brown  clay  adobe,  becoming  a  little  lighter  with 

depth. 
24-36  inches — Dark  brown  with  soft,  whitish  fragments.  Fragments  probably 
the  partially  weathered  parent  rock,  though  no  outcrops  of  the  rock  were 
seen  in  the  vicinity.  Previous  to  the  collection  of  the  sample,  Mr.  E.  C. 
Eckman,  who  mapped  the  area  as  the  Bureau  of  Soils  representative,  said 
in  substance:  "We  have  no  good  Diablo  in  the  area;  the  body  I  am 
directing  you  to  is  as  good  as  any,  but  it  is  pretty  brown. ' ' 

History:  Property  owned  by  Mr.  Huntington.  Farmed  to  grain  the  past  2 
years;  pasture  previously.  Data  from  the  son  of  the  tenant.  Sample  col- 
lected August  20,  1915. 

Depths  of  horizons: 

2-A        0-12  inches.  2-B       12-24  inches.  2-C       24-36  inches. 

No.  3 — Altamont  Clay  Loam 
Location:  1.4  miles  southeast  of  Walnut,  Los  Angeles  County,  on  the  shoulder  of 
a  low  hill,  about  200  feet  east  of  the  wagon  road  running  south  through 
the  hills.  The  station  was  selected  so  that  the  texture  was  about  right, 
for  in  a  very  short  distance  there  were  variations  from  a  heavy  dark  clay 
loam  or  clay  adobe  to  the  light  clay  loams. 


1919]  Pendleton:   A  Study  of  Soil  Types  491 

Soil:    0-36  inches — A  medium  textured  brown  friable  clay  loam.     The  soil  column 
throughout  was  more  or  less  filled  with  small  soft  whitish  fragments,  por- 
tions of  the  parent  rock. 
36  inches — The  weathered  parent  rock  was  encountered. 
History :    A.  T.  Currier,  owner.     The  field  is  in  pasture,  and  has  not  been  culti- 
vated for  forty  years,  to  the  knowledge  of  the  ranch  foreman.     The  soil  is 
probably  virgin.     Sample  collected  August  20,  1915. 
Depths  of  horizons: 

3-A        0-12  inches.  3-B       12-24  inches.  3-C       24-36  inches. 

No.  4 — Altamont  Clay  Loam 

Location:  On  a  hillside  a  few  feet  above  the  Cahuenga  Pass  (Burbank  road), 
near  Oak  Crest,  Los  Angeles  County.  Just  a  few  feet  from  the  U.  S. 
Bureau  of  Soils  station  for  the  type  in  the  San  Fernando  area.  (For  map, 
see  the  map  under  sample  no.  25.) 

Soil:    0-14  inches — A  dark  brown  clay  loam. 

14-36  inches — A  yellowish  brown  loam,  grading  into  the  weathered,  thin  bed- 
ded shales  at  about  36  inches. 

History :  Roadside,  above  the  big  cut  on  the  road,  probably  never  tilled.  The  sur- 
face is  not  so  steep  but  that  it  could  be  well  tilled;  some  of  the  soil  in 
the  immediate  vicinity  is  cultivated  to  grain.  Sample  collected  August  21, 
1915. 

Depths  of  horizons: 

4-A        0-12  inches.  4-B       12-24  inches.  4-C       24-36  inches. 

No.  5 — Diablo  Clay  Adobe 

Location:  About  %  a  mile  north  of  Calabasas,  San  Fernando  Valley,  Los  Angeles 
County.  The  station  is  some  distance  up  the  hill  to  the  west  of  the  road 
running  north  from  the  Calabasas  store.  The  sample  was  collected  near 
the  top  of  the  hill,  to  the  northeast  of  the  oak  tree. 

Soil:  A  dark  gray  to  black  typical  clay  adobe.  Distinctly  heavy.  Digging  was 
very  difficult,  the  soil  coming  up  in  large,  very  hard  clods.  The  soil  was  of 
about  the  same  color  and  texture  down  to  the  bedrock  at  26  inches.  The 
bedrock  is  a  heavy  claystone  or  shale. 

History :  John  Grant,  Calabasas  P.  O.,  owner.  The  land  has  been  dry  farmed 
to  grain.  Presumably  there  had  been  no  additions  of  fertilizing  materials 
to  the  soil.     Sample  collected  August  21,  1915. 

Depths  of  horizons: 

5-A        0-14  inches.  5-B       14-26  inches.  26  inches.     Parent  rock. 

No.  6 — Diablo  Clay  Adobe 

Location:  In  Contra  Costa  County,  %  mile  west  of  Tassajero;  6  miles  east 
and  a  little  south  of  Danville.  Station  about  150  feet  up  the  hill  to  the 
south  of  the  road,  that  is,  about  one-third  of  the  way  up  the  hill. 

Soil:    0-34  inches — A  black  or  dark  gray  clay  adobe,  moist  at  10  inches. 

34-72  inches — A  dark  grayish  brown  subsoil,  becoming  lighter  below  the  third 
foot.  No  bedrock  within  the  6  foot  section,  nor  was  there  any  sign  of  any 
outcrop  in  the  vicinity.  The  slope  of  the  hill  moderate,  the  exposure 
north.  The  sample  was  collected  with  the  assistance  of  Mr.  L.  C.  Holmes 
and  Mr.  E.  C.  Eckman,  both  of  the  U.  S.  Bureau  of  Soils.  They  pro- 
nounced the  station  typical. 


492  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

History:  Property  owned  by  J.  J.  Johnson.  The  field  has  been  farmed  to  grain 
for  probably  60  years.  Formerly  the  rotation  was  pasture  one  year,  and 
grain  one  year;  now  the  practice  is  grain  two  years,  and  pasture  one  year. 
Sample  collected  September  2,  1915. 

Depths  of  horizons: 

6-A        0-12  inches.  6-B       12-24  inches.  6-C       24-36  inches. 

No.  7 — Altamont  Clay  Loam 

Location:    On  the  Mission  Pass  road,  a  little  less  than  2  miles  south  and  a  little 

west  of  Sunol,  Alameda  County.     About  100  feet  above  the  road,  between 

wooden  electric  power  poles  nos.  92/30  and  92/31. 
Soil:    0-34  inches — A  medium  brown  clay  loam,  considered  typical  by  Mr.  L.  C. 

Holmes  and  Mr.  E.  C.  Eckman  of  the  U.  S.  Bureau  of  Soils.     There  were 

slight  changes  in  texture. 
34  inches — A  stiff  clay  horizon. 
Inspection   of  a   deep   cut   on   the   roadside   near   the   location   of   the   sample 

station  showed  that  at  6  feet  and  deeper  there  existed  a  heavy  reddish  clay. 

In  the  immediate  locality  the  road  sections  showed  that  the  parent  rock 

was  deeper  than  the  6  foot  section.     The  slope  of  the  land  at  the  sample 

station  was  quite  steep. 
History:    Tom  Burns,  Irvington,  owner.     Field  has  been  in  pasture  for  the  past  3 

years  at  least,  and  probably  for   a  much  longer   time.     Sample   collected 

September  2,  1915. 
Depths  of  horizons: 

7-A        0-12  inches.  7-B       12-24  inches.  7-C       24-36  inches. 

No.  10 — San  Joaquin  Sandy  Loam 

Location:  North  Sacramento,  Sacramento  County;  }4  mile  east  of  tile  factory, 
across  the  road;  opposite  poles  57/32  and  57/33,  75  feet  southeast  from  the 
State  Highway. 

Soil:    0-26  inches — A  brownish  red  sandy  loam,  slightly  hog  wallowed,  and  very 
slightly  rolling. 
26-36  inches — A  sandy  clay  loam. 
36  inches — A  hard  hardpan. 

History :  Owner  not  known,  the  district  now  being  subdivided,  the  property  being  a 
portion  of  the  old  ' '  Hagan  Grant. ' '  A  near-by  resident  gave  the  following 
information :  ' '  The  land  has  not  been  cultivated  for  the  past  15  years  or 
more.  The  land  is  said  to  have  been  farmed  to  grain  at  one  time  for  a  few 
years,  but  the  '  soil  is  too  light  for  wheat,  it  grows  nothing  but  filaree. '  ' ' 
The  principal  use  has  been  for  cattle  and  sheep  pasture.  Sample  collected 
March  28,  1916. 

Depths  of  horizons: 

10-A        0-12  inches.  10-B       12-24  inches.  10-C       24-36  inches. 

No.  11 — San  Joaquin  Sandy  Loam 

Location :  Four  miles  west  of  Lincoln,  Placer  County,  at  the  l '  Road  Corners, ' ' 
in  the  southeast  field,  10  feet  east  of  the  west  fence  and  60  feet  south  of 
the  north  fence. 


1919J  Pendleton:   A  Study  of  Soil  Types  493 

Soil:    A  gently  hog  wallowed,  sandy  loam,  with  some  deeper   depressions,  prob- 
ably stream  channels.     Sample  slightly  gravelly. 
0-12  inches — Brownish  or  reddish  brown  sandy  loam. 
12-17  inches — Sandy  clay  loam  or  clay,  color  the  same. 
17-23  inches — A  stiff  reddish  brown  clay. 
23  inches — A  hard  hardpan. 
History:    Mr.  Frank  Dowd,  owner.     The  land  has  been  planted  to  wheat  for  the 
past  20  or  25  years;   previous  to  that  time  it  was  used  for  pasture.     Six 
to  10  or  12  bushels  of  wheat,  and  8  to  20  bushels  of  barley  is  the  production 
of  this  soil  in  the  locality.     The  soil  is  usually  fallowed  on  alternate  years. 
Land  held  at  from  $30  to  $50  per  acre.     Sample  collected  March  28,  1916. 
Depths  of  horizons: 

11-A        0-11   inches.  11-B       11-17  inches.  11-C       17-23  inches. 


No.  12 — San  Joaquin  Sandy  Loam 

Location:   About  6  miles  west  of  Wheatland,  Sutter  County.     Near  a  road  corner, 
in  a  little  swale  west  of  a  knoll,  15  feet  east  of  the  westerly  fence  of  field, 
and  150  feet  south  of  the  north  line  of  the  westerly  road. 
Soil:    Texture  slightly  heavy,  and  barely  enough  sand  for  a  sandy  loam,  but  the 
best  found  for  several  miles.     Color  brownish  red,  the  same  throughout  the 
entire  depth. 
0-18  inches — Light,  fine  textured,  sandy  loam. 
18-31  inches — Heavy  sandy  clay  loam,  running  into  a  stiff  clay. 

31  inches — Hardpan,    sandy    and    somewhat    soft.      The    ground   was    very 
moist  at  this  time. 
History:    Very  evidently  pasture  for  sheep  and  cattle.     No  signs  of  having  been 
cultivated  for  several  years,  at  least.     The  cover  is  of  a  number   of  low 
annuals — Orthocarpus,  Trifolium,  Centaurea,  and  others.     Sample  collected 
March  29,  1916. 
Depths  of  horizons: 

12- A        0-12  inches.  12-B      12-18  inches.  12-C       18-31  inches. 


No.  13 — San  Joaquin  Sandy  Loam 

Location:    Three  and  three-quarters  miles  east  of  Elk  Grove,  Sacramento  County. 
On  the  Sheldon  road,  about  30  feet  northwest  from  the  fence  on  the  north 
side  of  the  road.     About  200  feet  southwest  from  where  a  house  formerly 
stood. 
Soil:    A  reddish   brown  sandy  loam,   approaching  a  loam;    becoming   redder   in 
color  with  increasing  depth. 
0-14  inches — Heavy  sandy  loam. 
14-22  inches — Clay  loam. 
22-29  inches — Heavy  clay  loam. 
29  inches — Compact  hardpan. 
History:    Wackman  Brothers,  Elk  Grove,  owners.     The  land  has  not  been  plowed 
or  farmed  for  at  least  15  years.     The  land  is  held  at  about  $50  per  acre. 
Sample  collected  March  30,  1916. 
Depths  of  horizons: 

13-A        0-12  inches.  13-B      12-22  inches.  13-C       22-29  inches. 


494  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

No.  14 — Hanford  Fine  Sandy  Loam 

Location:    One  mile  southeast  of  the  Sheldon  road,  3^  miles  east  of  Elk  Grove, 
Sacramento  County.     On  the  southwest  side  of  the  secondary  road,  in  al- 
falfa field,  about  25  feet  from  the  fence.     Station  on  a  little  rise. 
Soil:    0-11  inches — A  medium  brown  micaceous  heavy  fine  sandy  loam. 

11-24  inches — A   dark  gray  to  black  fine  sandy  loam,  grading  into   the   fol- 
lowing. 
24-36  inches — Brown  fine  sandy  loam.     Water  table  at  32  inches. 
History:   Mrs.  A.  C.  Freeman,  Elk  Grove,  owner.     Land  planted  to  alfalfa.     Good 
growth.     No  irrigation.     Willows  as  well  as  alders  and  river  ash  along  the 
sloughs.     Many  scattering  valley   oaks.     The  land  is   subject   to   overflow 
from  the  Cosumnes  Eiver,  as  it  lies  low  in  the  river  bottom,  and  shallow 
stream  channels  and  sloughs  are  frequent.     Sample  collected  March  30,  1916. 
Depths  of  horizons: 

14-A        0-12  inches.  14-B       12-24  inches.  14-C       24-36  inches. 

No.  15 — Hanford  Fine  Sandy  Loam 

Location:  North  of  Woodbridge,  San  Joaquin  County,  along  the  State  Highway, 
less  than  *4  mile  south  of  the  road  running  westerly  from  Acampo  to  the 
highway.  Station  in  a  vineyard,  with  almond  trees  along  the  roadside,  20 
feet  northeast  of  "change  telephone  pole,"  200  feet  north  of  pine  tree 
at  the  gateway  on  the  opposite  side  of  the  highway.  (For  map,  see  under 
sample  16.) 

Soil:  Texture  a  rather  coarse  fine  sandy  loam;  it  was  hard  to  find  a  good  fine 
sandy  loam.  Color  when  moist  was  a  medium  brown  throughout  the  3  foot 
section ;  the  field  color  was  a  light  grayish  brown. 

History:  Mike  Nolan  estate,  owner.  The  vineyard  is  of  Tokay  grapes,  10  to  12 
years  old.  The  land  is  held  at  $300  to  $400  per  acre.  It  is  said  to  be  a 
losing  game  to  farm  this  land  to  grapes  at  this  valuation.  Sample  col- 
lected March  30,  1916. 

Depths  of  horizons: 

15-A        0-12  inches.  15-B       12-24  inches.  15-C       24-36  inches. 

No.  16 — Hanford  Fine  Sandy  Loam 

Location :  Along  the  road  north  of  Woodbridge,  San  Joaquin  County.  In  a  young 
pear  orchard  about  65  feet  west  of  the  highway,  and  about  95  feet  north 
of  the  north  abutments  of  the  bridge  over  Mokelumne  Eiver. 

Soil:  A  medium  brown  fine  sandy  loam,  similar  throughout  the  soil  column  of 
three  feet.  This  soil  is  of  the  recent,  flood-plain  phase  of  the  type,  though 
this  station  is  not  known  to  have  been  under  water  for  a  number  of  years, 
at  least.  There  is  only  a  comparatively  narrow  shelf  of  this  phase  between 
the  older,  higher  phase,  and  the  river. 

History:  A.  Pen-in,  Woodbridge,  owner.  The  land  had  always  been  in  brush 
and  pasture  until  it  was  cleared  and  planted  to  pears  in  1911.  Value 
about  $500  per  acre.     Sample  collected  March  30.  1916. 

Depths  of  horizons: 

16-A        0-12  inches.  16-B       12-24  inches.  16-C       24-36  inches. 


1919]  Pendleton:   A  Study  of  Soil  Types  495 

No.  17 — San  Joaquin  Sandy  Loam 
Location :    A  short  distance  south  of  the  east  and  west  road  that  runs  east  to 
Thalheim,  San  Joaquin  County.     The  station  was  on  a  slight  knoll  75  feet 
south  of  a  canal,  and  the  same  distance  east  of  the  secondary  road  running 
north  and  south;  not  far  from  a  vacant  barn. 
Soil:    0-12  inches — Eeddish  brown. 
12-21  inches — Slightly  redder. 
21  inches — Hardpan. 

The  surface  had  the  characteristic  hog  wallows,  and  the  usual  scant  vegeta- 
tion of  grasses  and  herbs,  "filaree"  being  abundant;    yet  all  vegetation 
was  more  abundant  than  that  in  pastured  fields. 
History :    Rev.  Frank  Hoffman,  Acampo,  owner.     Apparently,  the  land  has  not 

been  cultivated  in  recent  years.     Sample  collected  March  31,  1915. 
Depths  of  horizons: 

17-A        0-12  inches.  17-B       12-21  inches. 

No.  18 — San  Joaquin  Sandy  Loam 
Location  :    Two  and  one-half  miles  northwest  of  Madera,  Madera  County.     Along- 
State  Highway,  75  to  100  feet  southwest  of  the  paved  road,  at  telephone 
pole  92/29;  across  the  highway  from  the  driveway  to  the  house. 
Soil:    0-5  inches — A  light  reddish  brown  sandy  loam.     A  noticeable  plow  pan  at 
5   inches. 
5-21  inches — A  light  brownish  red  sandy  loam,  becoming  heavier  below. 
21-30  inches — Quite  compact  heavy  sandy  loam. 
30  inches  and  deeper — A  very  compact  hardpan. 

Topography  very  gently  rolling,  hog  wallows  well  developed,  though  consider- 
ably degraded  by  cultivation.  Barley  grain  not  growing  well  in  the  lower 
spots. 
History:  Cropped  for  probably  20  years  to  grains;  barley  at  present.  Land  used 
for  pasture  previous  to  grain  farming.  A  good  yield  is  8  sacks,  varying 
from  that  down  to  little  or  nothing.  Miller  and  Lux,  owners.  Sample  col- 
lected April  11,  1916. 
Depths  of  horizons: 

18-A        0-12  inches.  18-B       12-24  inches.  18-C       24-30  inches. 

No.  19 — Hanford  Fine  Sandy  Loam 

Location:    Eight  miles  east  of  Waterford,  Stanislaus  County,  near  Robert's  Ferry 
bridge.     About  75  feet  west  of  the  road  that  runs  south  from  the  bridge 
onto  the  bluff.     About  450  feet  north  of  the  driveway  to  the  Sawyer  place. 
Twenty-five  feet  inside  of  the  fence,  in  the  alfalfa  field. 

Soil:  Medium  brown  fine  sandy  loam;  a  good  brown  color  when  moist.  Texture 
somewhat  variable,  some  rounded  gravels  up  to  the  size  of  a  hen's  egg. 
Topography  undulating,  and  more  or  less  terraced,  due  to  the  old  stream 
channels. 

History:  G.  H.  Sawyer,  Waterford,  owner.  Alfalfa  planted  in  1915,  looks  well. 
Land  previously  planted  to  barley  and  wheat,  with  a  production  about  as 
follows:  barley,  14  sacks  is  considered  good;  wheat  with  12  sacks  is  good, 
with  6  sacks  a  low  average.  Value  of  the  land  as  recently  determined  in 
court,  in  a  case  of  flood  damage  by  a  canal  break,  is  $100  per  acre.  On  an 
adjoining  piece  of  land  young  walnut  trees  are  doing  very  well.  Sample 
collected  April  11,  1916. 

Depths  of  horizons: 

19-A        0-12  inches.  19-B      12-24  inches.  19-C       24-36  inches. 


496  University  of  California  Publications  in  Agricultural  Sciences        [Vol.  3 

No.  20 — Han  ford  Fine  Sandy  Loam 

Location  :  Near  Hopeton,  Merced  County,  14  miles  north  of  Merced.  Less  than 
14  mile  north  from  the  road  corners,  15  feet  east  of  the  east  fence  of  the 
road,  and  150  feet  south  of  irrigating  ditch. 

Soil:  A  good  medium  brown  fine  sandy  loam.  The  color  is  especially  good  when 
the  soil  is  moist.  The  topography  is  slightly  uneven  because  of  the  old 
stream  channels.  Going  north  along  the  road  from  the  cross  roads  the 
soil  is  quite  gravelly  at  first,  but  the  texture  gradually  becomes  heavier, 
with  less  gravel.  At  the  sample  station  the  texture  is  a  rather  heavy  fine 
sandy  loam. 

History:  J.  G.  Euddle,  Snelling,  owner.  The  field  is  planted  to  alfalfa,  as  are 
most  of  the  Hanford  soils  in  the  locality.  The  land  is  not  subject  to 
overflow.     Sample  collected  April  13,  1916. 

Depths  of  horizons: 

20-A        0-12  inches.  20-B       12-24  inches.  20-C       24-36  inches. 


No.  21 — San  Joaquin  Sandy  Loam 

Location:    Near  Nairn  Station,  Merced  County.     About  14  mile  west  of  the  rail- 
road, 50  feet  north  of  the  private  ranch  road,  and  120  feet  east  of  the  field 
gate  across  the  road.     About  4  miles  northwest  of  Merced. 
Soil:    A  good  brownish  red  San  Joaquin  color.     Texture  a  sandy  loam,  grading 

into  a  clay  loam  or  clay  at  about  24  inches. 
Depths  of  horizons: 

24-27  inches — A  heavy   clay. 
27  inches — Hardpan. 

The  same  was  taken  from  near  the  top  of  one  of  the  hog  wallow  elevations. 
The  topography  is  gently  rolling. 
History:  F.  W.  Henderson,  Merced,  owner.  At  the  present  time  the  land  is  used 
as  pasture.  It  has  been  plowed  at  some  time  in  the  past.  The  present 
growth  of  wild  herbage  {Lepidium,  small  grasses,  Cryptanthe,  etc.)  is 
meager.  Sample  collected  April  13,  1916. 
Depths  of  horizons: 

21-A        0-12  inches.  21-B       12-24  inches.  21-C       24-27  inches. 


No.  22 — Hanford  Fine  Sandy  Loam 

Location:  A  short  distance  north  of  Basset,  Los  Angeles  County,  on  the  main 
road  north  from  Basset  station.  The  sample  was  collected  in  a  walnut 
grove  100  feet  east  of  the  road  and  250  feet  south  of  the  driveway  to  the 
ranch  house. 

Soil:  A  good  medium  brown  when  moist,  and  a  light  grayish  brown  when  dry. 
Mr.  L.  C.  Holmes,  of  the  U.  S.  Bureau  of  Soils,  described  the  soil  at  the 
time  of  collection  as  being  "all  a  little  browner,  and  with  a  little  more 
color  than  a  good  Hanford. ' ?  There  was  a  very  slight  color  change  at 
about  a  foot,  the  soil  below  was  grayer.  Texture  a  good  fine  sandy  loam, 
with  practically  no  change  in  the  3  foot  column.  Topography  smooth. 
The  texture  varies  quite  rapidly  from  place  to  place  in  the  field.  Some 
big  washes  of  typical  intermittent  streams  are  found  not  far  to  the  north 
and  west. 


1919]  Pendleton:   A  Study  of  Soil  Types  .497 

History:  C.  N.  Basset,  of  Basset  and  Nebeker,  Santa  Monica,  owner.  The  land 
is  planted  to  walnuts,  and  the  trees  are  about  10  years  old.  They  are 
doing  well,  some  replants  are  found.  The  trees  are  irrigated.  Sample  col- 
lected May  22,  1916. 

Depths  of  horizons: 

22-A        0-12  inches.  22-B      12-24  inches.  22-C       24-36  inches. 


No.  23 — Hanford  Fine  Sandy  Loam 

Location:  South  and  west  of  the  town  of  Anaheim,  Orange  County.  Within  a 
radius  of  20  feet  of  where  the  official  Bureau  of  Soils  sample  was  taken. 
Thirty  feet  east  of  side  road,  and  100  feet  north  of  main  east  and  west  road. 

Soil:  Brown  fine  sandy  loam,  possibly  a  little  more  silty  than  no.  22,  but  not 
heavy  enough  for  a  heavy  fine  sandy  loam.  Dry  field  color  a  light,  grayish 
brown.  Topography  smooth,  no  stream  channels  visible.  Irrigation  in  fur- 
rows. Soil  similar  to  about  62  inches,  a  little  more  grayish  at  18  inches, 
the  change  being  gradual.  At  62  inches  a  gray  clean  sand,  or  fine  sand, 
was  found. 

History:  S.  J.  Luhring,  R.  F.  D.  no.  4,  owner.  The  field  was  planted  to  Valencia 
oranges  in  1913 ;  previously  to  grapes  and  miscellaneous  crops.  Sample 
collected  May  23,  1916. 

Depths  of  horizons: 

23-A        0-12  inches.  23-B      12-24  inches.  23-C       24-36  inches. 


No.  24 — Hanford  Fine  Sandy  Loam 

Location:    Southeast  of  the  center  of  Los  Angeles,  half  way  from  Magnolia  Ave- 
nue on  Fruitland  Road,  to  Salt  Lake  Railroad  on  the  east.     South  side  of 
the  road  about   60  feet  from  center,  in  edge  of  corn  field.     Just  across 
road  from  east  end  of  east  cypress  trees. 
Soil :   A  medium  brown  fine  sandy  loam  when  moist ;  color  in  the  field  is  a  grayish 
brown.     Micaceous.      Topography  level,   no   stream   channels   seen   nearby. 
Color  of  body  variable.     Sample  location  in  the  browner  phase.     Toward 
south  and  east  along  the  railroad  and  Arcadia  Avenue  the  color  is  much 
grayer,  and  even  black  when  moist.     Texture  within  the  body  is  very  vari- 
able, though  always  within  the  fine  sandy  loam  group. 
0-36  inches — Fine  sandy  loam,  grayer  below. 
36-37  inches — Layer  of  grayish  sand  and  fine  sand. 
37-72  inches — Fine  sandy  loam,  heavier  in  streaks. 
History :    C.  D.  Templeman,  R.  F.  D.  no.  2,  Box  178,  Los  Angeles,  owner.     Land 
has  been  in  truck  for  10  or  12  years.     Only  fertilizer,  barnyard  manure. 
Sample  collected  May  24,  1916. 
Depths  of  horizons: 

24-A        0-12  inches.  24-B      12-24  inches.  24-C       24-36  inches. 


No.  25 — Hanford  Fine  Sandy  Loam 

Location:  Near  Van  Nuys,  Los  Angeles  County;  near  official  sample  station. 
Seventy-five  feet  west  of  center  of  road,  between  fourth  and  fifth  rows  of 
apricot  trees  north  from  boundary. 


498  University  of  California  Tuolications  in  Agricultural  Sciences        [Vol.  3 

Soil:  A  good  medium  brown  fine  sandy  loam;  the  field  color  a  grayish  brown. 
The  texture  uniform  throughout  the  3  foot  section,  with  a  little  gravel  occa- 
sionally. Also  the  texture  is  variable  to  about  the  usual  degree,  in  the 
field  distribution.  The  color  is  slightly  lighter  at  about  2  feet  and  below 
throughout  the  C  feet,  with  a  little  variation  in  an  increasing  amount  of 
coarser  sands. 

History:  Chase,  Eiverside,  owner  (?).  Planted  to  apricots,  2  years  old.  Inter- 
planted  to  melons.     Sample  collected  May  24,  1916. 

Depths  of  horizons: 

25-A        0-12  inches.  25-B       12-24  inches.  25-C       24-36  inches. 

No.  26 — San  Joaquin  Sandy  Loam 

Location:    On  the  high  bluffs  about  iy±  miles  southeast  of  Del  Mar  station,  San 
Diego  County,  close  to  the  road  that  runs  back  along  the  main  ridge.    About 
50  feet  north  of  the  road  where  it  swings  south  to  get  around  the  head  of 
the  big  arroyo  from  the  north. 
Soil:    A  brownish  red  sandy  loam.     Surface  covered  with  a  moderate  growth  of 
the  low  chapparal  common  to  these  exposed  ridges.     Soil  heavily  laden  with 
iron  concretions.     Surface  has  the  usual  hog  wallows  characteristic  of  the 
San  Joaquin  series. 
0-  6  inches — Eeddish  brown  sandy  loam,  many  concretions.     Dry. 
j6— 13  inches — Clay  (sandy),  reddish  in  cracks,  and  bluish  inside  of  lumps  and 

where  not  weathered. 
13-22  inches — Clay,  mostly  bluish  gray. 
22-38  inches — Boring  very   difficult,   due   to   the   heavy   nature   of   the   clayey 

moist  material.     Color  bluish. 
About  40  inches — Hardpan.     Very  compact. 
History :    Probably  never  farmed.     Recently  streets  cleared,  and  an  attempt  made 
to  sell  lots  for  building.     Value  for  agriculture — none  without  irrigation. 
Sample  collected  May  25,  1916. 
Depths  of  horizons: 

26-A        0-6  inches.  26-B        6-13  inches.  26-C       13-22  inches. 


UNIV.    CALIF.    PUBL.    AGR,    SCI.    VOL.    3 


[PENDLETON]     PLATE    43 


A  general  view  in  the  greenhouse,  where  all  the  pot  culture  work  was  carried 
on.  The  entire  right  hand  bench  was  devoted  to  this  study,  also  half  again  as 
much  space  not  visible  in  the  print. 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]     PLATE    44 


Diablo  Clay  Adobe — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.   1.     Oats   and  bur  elover.     Left  to  right — Soil   1,  pot   1;    soil   2,  pot   2; 
soil  5,  pot  1 ;  soil  6,  pot  3. 


Diablo  Clay  Adobe — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Oats.     Left  to  right— Soil  1,  pot  1;  soil  2,  pot  3;  soil  5,  pot  2;  soil  6, 
pot  2. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]     PLATE    45 


Diablo  Clay  Adobe — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Bur  clover.     Left  to  right — Soil  1,  pot  1;  soil  1,  pot  2;  soil  1,  pot  3. 


Diablo  Clay  Adobe — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Bur  clover.     Left  to  right— Soil  2,  pot  1;  soil  2,  pot  2;  soil  2,  pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[  PENDlLETON  ]     PLATE    46 


% 


1S&  >W^v 


W&H 


%il 


.*       :  :     ;        f 


Diablo  Clay  Adobe — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Bnr  clover.     Left  to  right — Soil  5,  pot  1;  soil  5,  pot  2;  soil  5,  pot  3. 


m 


Diablo  Clay  Adobe — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Bur  clover.     Left  to  right— Soil  6,  pot  lj  soil  6,  pot  2;  soil  6,  pot  3. 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]     PLATE    47 


Diablo  Clay  Adobe — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Bur  clover.     Left  to  right — Soil  1,  pot  1;   soil  2,  pot  2;   soil  5,  pot  2;    soil  6, 
pot  1. 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL,    3 


[PENDLETON]     PLATE    48 


t 


Diablo  Clay  Adobe — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 

Dwarf  milo  («)  following  oats.    Left  to  right — Soil  1,  pot  2;  soil  1, 


Fig.  1. 

pot  3;  soil  2,  pot  1  ;  soil  2,  pot  3;  soil  5 
pot  3. 


pot  1  ;  soil  5,  pot  3;  soil  6,  pot  2;  soil  6, 


• 


Diablo  Clay  Adobe — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Dwarf  milo  (b) following  oats  and  bur  clover.     Left  to  right — Soil  1, 


pot  1;  soil  1,  pot  3;  soil  2,  pot  1;  soil  2,  pot  3;  soil 
pot  1 ;  soil  6,  pot  3. 


5,  pot  1;  soil  5,  pot  3;  soil  6, 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  1     PLATE     49 


Diablo  Clay  Adobe — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Cowpeas,  following  wheat.    Left  to  right — Soil  1,  pot  1 ;  soil  1,  pot  2; 
soil  2    pot  1  ;  soil  2,  pot  2;  soil  5,  pot  1  ;  soil  5,  pot  2;   soil  (i,  pot  2;  soil  <i,  pot  3. 


Diablo  Clay  Adobe — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.   2.     Soy  beans,  following  barley.     Left   to   right — Soil   1,  pot   1;    soil   1, 

pot  2;  soil  2,  pot  1;  soil  2,  pot  3;  soil  5,  pot  1;  soil  5,  pot  2;  soil  6,  pot  1;  soil  6, 

pot  2. 


UNIV.    CALIF.    FUBL.    AGR.    SCI.    VOL, 


[  PENDLETON  ]     PLATE    50 


Altamont  Clay  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Cowpeas  B,  following  barley.     Left  to  right — Soil  3,  pot  1 ;   soil  3,  pot- 
soil  4,  pot  1;  soil  4,  pot  3;  soil  7,  pot  1;  soil  7,  pot  3. 


UNiV.    CALIF.    PUBL.    AGR.     SCI.    VOL.    3 


[PENDLETON]     PLATE    51 


Altamont  Clay  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.   1.     Soy  beans  A,  following  oats.     Left  to  right — Soil  3,  pot   1;    soil   3, 
pot  2;  soil  4,  pot  2;  soil  4,  pot  3;  soil  7,  pot  2;  soil  7,  pot  3. 


Altamont  Clay  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.    2.      Soy  beans   B,   following  Phaseolus.     Left   to   right — Soil    3,   pot   2 
soil  3,  pot  3;  soil  4,  pot  1;  soil  4,  pot  2;  soil  7,  pot  1;  soil  7,  pot  2. 


UNIV.    CALIF.    PUBL.    AGR.     SCI.    VOL. 


[  PENDLETON  ]     PLATE    52 


Altamont  Clay  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Dwarf  milo  A,  following  wheat.     Left  to  right — Soil  3,  pot  2 ;  soil  3, 
pot  3;  soil  4,  pot  1;  soil  4,  pot  3;  soil  7,  pot  1;  soil  7,  pot  3. 


Altamont  Clay  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Dwarf  milo  A,  following  bur  clover.     Left  to  right — Soil  3,  pot  1 ; 
soil  3,  pot  2;  soil  4,  pot  1;  soil  4,  pot  3;  soil  7,  pot  1 ;  soil  7,  pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]     PLATE    53 


Haxford  Fine  Sandy  Loam — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Dwarf  milo  A.     Left  to  right — Soil  14,  pot  2;  soil  15,  pot  2;  soil  16, 

pot  3 ;  soil  19,  pot  3 ;  soil  20,  pot  2 ;  soil  22,  pot  2 ;  soil  23,  pot  1 ;  soil  21,  pot  2 ; 

soil  2.1,  pot  1. 


Hanford  Fine  Sandy  Loam — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Dwarf  milo  A.     Left  to  right— Soil  15,  pot  1;  soil  15,  pot  2;  soil  15, 

pot  3;  soil  20,  pot  1;  soil  20,  pot  2;  soil  20,  pot  3;  soil  23,  pot  1;  soil  23,  pot  2; 

soil  23,  pot  3. 


1 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]     PLATE    54 


I 


Haxford  Fixe  Sandy  Loam — First  Crop 
Pota  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.   1.      Dwarf  milo  B.     Left  to  right — Soil  14,  pot  3;   soil  15,  pot  2;  soil  lb', 

pot   1  :  soil  H»,  pot  3;   soil  20,  pot  2;  soil  22,  pot  3;  soil  23,  pot  3;  soil  24,  pot  2; 

soil  25,  pot  •">. 


:i 


Haxford  Fine  Sandy  Loam — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Dwarf  milo  B.     Left  to  right— Soil  14,  pot  1;  soil  14,  pot  2;  soil  14, 

pot  3;  soil  22,  pot  1;  soil  22,  pot  2;  soil  22,  pot  3;  soil  23,  pot  1;  soil  23,  pot  2; 

soil  23,  pot  3. 


i 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]     PLATE    55 


Haxford  Fixe  Sandy  Loam — First  (jrop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.    1.     Soy   beans.     Left  to  right — Soil   14,  pot   1;    soil   15,  pot   1;    soil   16, 

pot  2;  soil   L9,  pot  2;  soil  20,  pot  3:  soil  22,  pot  1;  soil  23,  pot  3;  soil  24,  pot  1; 

soil   2.",  pot   3. 


Haxford  Fine  Sandy.  Loam — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.   2.     Soy  beans.     Left  to  right— Soil   14,  pot   1;    soil   14,  pot   2;    soil   14, 

pot  3;  soil  16,  pot  1;  soil  16,  pot  2;  soil  16,  pot  3;  soil  23,  pot  1;   soil  23,  pot  2; 

soil  23,  pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]     PLATE    56 


Haxford  Fine  Sandy  Loam — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Cowpeas  B.     Left  to  right— Soil  14,  pot  1;   soil  14,  pot  2;   soil  14, 
pot  3;  soil  22,  pot  1  ;  soil  22,  pot  2;  soil  22,  pot  3;  soil  23,  pot  1;  soil  23,  pot  2; 

soil  2:;,  pot  :;. 


*; 


Mi '  ££& 


A     I    A    ii^A    A    A*  A 


Hanford  Fine  Sandy  Loam — First  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Cowpeas  B.     Left  to  right — Soil  14,  pot  3;   soil  15,  pot  2;   soil  16, 

pot  2;  soil  19,  pot  2;  soil  20,  pot  2;  soil  22,  pot  2;  soil  23,  pot  2;  soil  24,  pot  1; 

soil  25,  pot  3. 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]    PLATE    57 


1 

i 

/ 

'J^ 

tf?*iLBgMi 

g^agfe 

i 

£gi 

^  "f 

£** 

* 

gMflpfc 

&t$m 

\ 

Hanford  Fixe  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.   1.     Barley,  following  soy  beans.     Left  to  right — Soil  14,  pot  2;   soil  15, 

pot   I  ;  soil   16,  pot  3;  soil  19,  pot  3;  soil  20,  pot  1;  soil  22,  pot  2;  soil  23,  pot  3; 

soil  24,  pot  •"> :   soil  2-"),  pot  1. 


Hanford  Fine  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Barley,  following  soy  beans.     Left  to  right — Soil  14,  pot  1;   soil  14, 

pot  2;  soil  14,  pot  3;  soil  19,  pot  1;  soil  19,  pot  2;  soil  19,  pot  2;  soil  19,  pot  3; 

soil  23,  pot  1;  soil  23,  pot  2;  soil  23,  pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]    PLATE    58 


|M      |  t  J 


] 


If  I 

V:' 


;«l»  v  !ii  Es&sJLJL'U 


MM 


?-<*izm? 


i**&m&>m«T^a&!'*  v&n  "•itfafiK^vss. 


IIaxford  Fine  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Wheat,  following  millet.     Left  to  right — Soil  14,  pot  1;  soil  15,  pot  1;  soil  16, 
pot  1;  soil  19,  pot  3;  soil  20,  pot  1;  soil  22,  pot  1;  soil  23,  pot  1;  soil  24,  pot  1; 

soil  25,  pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]    PLATE    59 


. 


Hanford  Fine  Sandy  Loam — Second  Crop 
Pots  of  same  ami  different  representatives  of  a  given  soil  type  compared. 
Wheat,  folio-wing  millet.     Left  to  right — Soil  16,  pot  1 ;  soil  16,  pot  2 ;  soil  16, 

pot  3;  soil  22,  pot  1  ;  soil  22,  pot  2;  soil  22,  pot  3;  soil  24,  pot  1;  soil  24,  pot  2; 

soil  24,  pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]    PLATE    60 


Hanford  Fixe  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.    1.     Barley,   following  cowpeas.     Left  to  right — Soil  14,  pot  2;   soil  15, 

pot  ::;  soil  16,  pot  2;  soil  ]9,  pot  2;  soil  20,  pot  1;  soil  22,  pot  3;  soil  23,  pot  3; 

soil   24,  pot   :'» ;   soil  2.1,  pot  1. 


'. 


Haxford  Fine   Sandy  Loam — Second  Chop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Barley,  following  cowpeas.     Left  to  right — Soil  19,  pot  1;   soil   ]9, 

pot  2;  soil  j  9,  pot  3;  soil  20,  pot  1;  soil  20,  pot  2;  soil  20,  pot  3;  soil  23,  pot  1; 

soil  23,  pot  2 ;  soil  23,  pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]    PLATE    61 


Hanford  Fine  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Oats,  following  milo.     Left  to  right — Soil  14,  pot  3;   soil  15,  pot  2; 

soil  16,  pot  2;  soil  19,  pot  1;  soil  20,  pot  2;  soil  22,  pot  1;  soil  23,  pot  3;  soil  24, 

pot  1 ;  soil  25,  pot  1. 


i 

**$*  / "       ;'    .-^ 

"  '  'f  '"BUiiiT ' '  i1  """^  £ 

1 

j 

1 1       ! 

^>  i 

| ! ! 

r 

■ 

i" 

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«           — — — -^ 

=  ■  -   — ■; 

■     _ 

Hanford  Fine  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  2.     Oats,  following  milo.     Left  to  right — Soil  14,  pot  1 ;   soil  14,  pot  2 ; 

soil  14,  pot  3;  soil  15,  pot  1;  soil  15,  pot  2;  soil  15,  pot  3;  soil  24,  pot  1;  soil  24, 

pot  2;  soil  24,  pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]    PLATE    62 


Hanford  Fine  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 

Melilotus  indica,  following  eowpeas.     Left  to  right — Soil  14,  Pot  1;  Soil  15, 
Pot  3;  Soil  16,  Pot  2;  Soil  19,  Pot  2;  Soil  20,  Pot  1. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]    PLATE    63 


■ 

"1 

T 

{/    : 

. 

■ 

-,/X 

.   '    S 

--     ■'*.                     .••'  \      [K 

9W& 


Hanford  Fine  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Melilotus  indica,  following  eowpeas.     Left  to  right — Soil  22,  Pot  2;  Soil  23, 
Pot  ]  ;  Soil  24,  Pot  1;  Soil  25,  Pot  1. 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]    PLATE    64 


Hanford  Fine   Sandy  Loam — Second  Chop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Melilotus  indica,  following  cowpeas.     Left  to  right — Soil  15,  Pot  1;  Soil  15, 
Pot  2;  Soil  15,  Pot  3;  Soil  23,  Pot  1. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]    PLATE    65 


IIanf-ord  Fine  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 

Melilotus  indica,  following  cowpeas.     Left  to  right— Soil  23,  Pot  2;  Soil  23, 
Pot  3;  Soil  25,  Pot  1 ;  Soil  25,  Pot  2;  Soil  25,  Pot  3. 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]    PLATE    66 


• 

V 

^      ngjjj^— 

■^HHBte^^P^^ 

-^■P\.    — 

-- 

Haxford  Fixe  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Bur  clover,  following  milo.     Left  to  right — Boil   14,  Pot   1 ;   Soil  15,  Pot  1; 
Soil  16,  Pot  2;  Soil  19,  Pot  1:  Soil  20,  Pot  1. 


Haxford  Fixe   Saxdy  Loam — Secoxd  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 

Bur  clover  following  milo.     Left  to  right— Soil  22,  Pot  1  ;    Soil   23,   Pot    1 
Soil  24,  Pot  1;  Soil  2o,  Pot  1. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]    PLATE    67 


Haxford  Fine   Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Bur  clover,  following  milo.     Left  to  right— Soil  19,  Pot  1;   Soil  19,  Pot  2; 
Soil  19,  Pot  3;  Soil  23,  Pot  1;  Soil  23,  Pot  2. 


*5k  t^tit 


Hanford  Fine  Sandy  Loam — Second  Crop 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Bur  clover,  following  milo.     Left  to  right— Soil  23,  Pot  3;   Soil  25,  Pot  1 
Soil  23,  Pot  2:  Soil  23,  Pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]    PLATE    68 


San  Joaquin  Sandy  Loam 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Eye.     Left  to  right— Soil  10,  pot  2;    soil  11,  pot  1;    soil  12,  pot  2;    soil   13, 
pot  3;  soil  17,  pot  3;  soil  18,  pot  1;  soil  21,  pot  1;  soil  26,  pot  1. 


UNIV.    CALIF.     FUBL.    AGR.    SCI.    VOL. 


r  PENDLETON  ]    PLATE    69 


San  Joaquin  Sandy  Loam 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Melilotus  indica.    Left  to  right— Soil  10,  pot  1;  soil  11,  pot  3;  soil  12, 
pot  2;  soil  13,  pot  1;   soil  17,  pot  3;  soil  18,  pot  3;  soil  21,  pot  2;  soil  28,  pot  1. 


[■       ' 

Lti 

_ 

'-  ' :  '■■ 

••  1 

\ 

-' 

1 

Iff 

■I: 
mm 

w 

Br  ^ 

■    - 

-  '-  "     -;-> 

L___' 

- 

San  Joaquin  Sandy  Loam 

Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 

Fig.  2.  Melilotus  indica.  Left  to  right — Soil  13,  pot  1;  soil  13,  pot  2;  soil  13, 
pot  3;  soil  17,  pot  1;  soil  17,  pot  2;  soil  17,  pot  3;  soil  26,  pot  1;  soil  28,  pot  2; 
soil  26,  pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]    PLATE    70 


San  Joaquin-  Sandy  Loam 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Eye.     Left  to  right — Soil  10,  pot  1;    soil  10,  pot  2;    soil  10,  pot  3;   soil   18, 
pot  1;  soil  18,  pot  2;  soil  18,  pot  3;  soil  26,  pot  1;  soil  26,  pot  2;  soil  26,  pot  3. 


UNIV.    CALIF.     PUBL.    AGR.    SCI.    VOL,    3 


[PENDLETON]    PLATE    71 


San  Joaquin  Sandy  Loam 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Barley.     Left  to  right— Soil  10,  pot  3;  soil  11,  pot  2;  soil  12,  pot  3; 
soil  13,  pot  1;  soil  17,  pot  3;  soil  18,  pot  2;  soil  21,  pot  3;  soil  26,  pot  1. 


San  Joaquin  Sandy  Loam 

Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 

Fig.  2.  Barley.  Left  to  right— Soil  10,  pot  1 ;  soil  10,  pot  2 ;  soil  10,  pot  3 ; 
soil  18,  pot  1;  soil  18,  pot  2;  soil  18,  pot  3;  soil  26,  pot  1;  soil  26,  pot  2;  soil  23, 
pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]    PLATE    72 


Jf^fe^WjES! 


San  Joaquin  Sandy  Loam 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Oats.     Left  to  right — Soil  10,  pot  1;   soil  11,  pot  1;   soil  12,  pot  2; 
soil  13,  pot  1;  soil  17,  pot  2;  soil  18,  pot  3;  soil  21,  pot  1;  soil  28,  pot  3. 


San  Joaquin  Sandy  Loam 

Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 

Fig.  2.  Oats.  Left  to  right— Soil  11,  pot  1;  soil  11,  pot  2;  soil  11,  pot  3; 
soil  17,  pot  1;  soil  17,  pot  2;  soil  17,  pot  3;  soil  21,  pot  1;  soil  21,  pot  2;  soil  21. 
pot  3. 


UNIV.    CALIF,    PUBL.    AGR.    SCI.    VOL.    3 


[PENDLETON]    PLATE    73 


i     > 


San  Joaquin  Sandy  Loam 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.  1.     Wheat.     Left  to  right— Soil  10,  pot  1. ;  soil  11,  pot  3;   soil  12,  pot  1; 
soil  13,  pot  ]  ;  soil  17,  pot  1;  soil  18,  pot  2;  soil  21,  pot  1;  soil  26,  pot  3. 


San  Joaquin  Sandy  Loam 

Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 

Fig.  2.  Wheat.  Left  to  right— Soil  10,  pot  1;  soil  10,  pot  2;  soil  10,  pot  3; 
soil  13,  pot  1;  soil  13,  pot  2;  soil  13,  pot  3;  soil  17,  pot  1;  soil  17,  pot  2;  soil  17, 
pot  3. 


UNIV.    CALIF.    PUBL.    AGR.    SCI.    VOL.    3 


[  PENDLETON  ]    PLATE    74 


fc'- 


IV.vi 


i 


San  Joaquin  Sandy  Loam 
Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 
Fig.   1.     Bur  clover.     Left  to  right— Soil  10,  pot  2;    soil   11,  pot  2;    soil   12, 
pot  3;  soil  13,  pot  1;  soil  17,  pot  3;  soil  18,  pot  2;  soil  21,  pot  1;  soil  26,  pot  3. 


San  Joaquin  Sandy  Loam 

Pots  of  same  and  different  representatives  of  a  given  soil  type  compared. 

Fig.  2.  Bur  clover.  Left  to  right— Soil  10,  pot  1;  soil  10,  pot  2;  soil  10, 
pot  3;  soil  18,  pot  1;  soil  18,  pot  2;  soil  18,  pot  3;  soil  26,  pot  1;  soil  26,  pot  2; 
soil  26,  pot  3. 


